Warm welcome to everybody listening to this conference. This is Gurit first half year 2020 results. I'm joined by Philippe Wirth, our CFO. My name is Rudolf Hadorn. We have that call due to COVID-19 as an event, as a meeting is not opportune these days. The presentation is split in two parts. First, the results presentation, which is recorded in the usual way, and then the Q&A, which is separate, is not going to be recorded. In order to give you a bit guidance for those people who are on webcast, I will indicate the slides. By which I would ask you to focus now on slide two, which is the introductory statement. As we are on a call, I read this down.
This presentation may include forward-looking statements that reflect the intentions, beliefs, and our current expectations and projections of Gurit Holding AG, about the future results of operations, financial condition, liquidity, performance, and similar circumstances. Such statements are made on the basis of assumptions and expectations, which may prove to be erroneous, although Gurit Holding AG believes them to be reasonable at this point in time. I would like to focus now on the next slide, which is our vision and mission. We are on the way with passion for a sustainable future. Gurit has an important role to play in its wind business particularly, but also its lightweighting business to help reduce CO2 emissions globally, providing a better form of energy. Also making heavier things light in our undertakings of lightweighting, which is in essence, aerospace and marine and industry.
With that, I would like to focus on slide number five, which is the market outlook for wind, aerospace, marine, and industry. We have perceived a strong wind energy demand in 2020 despite COVID. The sector has been classified of strategic nature, which helped in the stop and goes, which we have perceived over the last six months, starting in China in early quarter one, and keeping us busy and stressed until now. It's not yet over yet. What we believe to be a short-term matter is taking its time. Those stop and goes had difficulties for us, and I will cover that in the summary of the presentation. Our team did very well in helping and working with the customers to keep them going at any location in the world they were operating in.
We expect in terms of demand curve, that is the gigawatt installed per year, which is indicated on the following slide. We expect that demand to be an S-curve. We have subsidy effects, which affect the years 2019 and 2020 and 2021, particularly a little bit of a pull-forward effect. Our customers, undertaking every possible step to install as much capacity they can still do under the subsidies. That leads to a certain pull forward. We'll have a 2022 and 2023 effect that the reduction is a bit, market. What is important shorter term, 2021 will be a record year with 77 GW installed. That is current market expectations of Wood Mackenzie, of which we take the numbers we are talking about here. More importantly, in order to sustain, to grow, and to offer lower cost energy, we measure that levelized cost of energy.
The cost of a wind turbine over its lifetime expressed in EUR or whatever currency per kilowatt-hour produced. The trends to grow the turbine size in order to basically cover more wind surface under the blades is continuing at unchanged pace. Also means that we will see onshore and offshore much bigger turbines in the future. We have crossed the 100 m blade length last year, actually, and we see a lot of new blades coming in the ranges of 85 m-90+ m , not only onshore, but also offshore. As a consequence, the number of blades produced, the blade number, we expect to reduce from about 70,000 in 2020 to about 45,000 in 2023. Those blades are at much higher length on average and at much, much bigger volume per blade.
That actually the consume of core materials, glass fibers, and the related materials will grow despite the reduction of the blade size. Global wind customers expect supply partners which are global as well. Not only for the products, looking for proximity in each continent or subcontinent, but also a higher service presence. The service presence is particularly meaningful for tooling and kitting. We also, in our strategy, try to reflect that by collocating more and more kitting sites where we finish the core into the sheets the customer needs to put into the blade mold, as well as the foam factories. Put them together, eliminate the distance. There is also not only a cost benefit, there is also sustainability benefit because we transport less material crisscross around the world. Those partners or customers, they also expect cost out and cycle time reduction capability.
As I mentioned, the blades are reaching very, very big sizes and very high weights. Historically, 10 years ago, from 8 tons per blade ballpark to now long blades, 30 tons, 50 tons per blade. That affects cycle times of laying up the blade in the mold, but also curing the blades. On that side, Gurit and other suppliers to the market are expected to offer cycle time reduction capabilities and help the customers to have an optimum capacity utilization and lowest possible cost. Also, the product and service bundling. We have made the first step with the acquisition of the kitting business, JSB, in 2018. Customers expect to de-complex the supply chain. Less partners, but more capable partners, global partners with those capabilities to help reduce cost and cycle time. We reflect that in our strategy with a focus on China more than 10 years ago.
With Mexico in 2019 and 2020, with India in 2021, early 2022, and an offering expansion. We spoke with the kitting acquisition and further steps which are possible for Gurit. That is, in short, the wind market environment we see for the next couple of years. In aerospace, we were hit by the COVID-19 impact on demand, like everybody being exposed to the aerospace industry. We have seen a sharp decline in global passenger aircraft markets, more than 50% expected. I refer here to the statements of the CEOs of Airbus and also Boeing. We expect, consequently, a gradual recovery, which will take multi-year to pre-pandemic levels. This is not going to be a short swing around.
We also expect, likely, that the industry will consolidate more because there is less cake for the same amount of participants, and people try to avoid to be under critical in their business size. For the marine and industry market environment, a little bit different for the industry, depending where composite materials are being deployed in the global markets. Marine and industry with a slight decline, mainly also due to COVID and lower investment propensities on spending. I would like now to focus your attention on slide six, which is the global power generation. In that global power generation chart, we see that the lower stacks there, which is solar and wind.
If you take, for instance, 2028 with 1.5 and 1.2, we clearly see that the potential of renewables is big, because over the years of 2017-2028, if you look at that chart, the amount of non-renewable energy creation is actually not reducing. The renewable sources of wind and solar just take care of the growth of the demand. For instance, if you look at the year 2020, we have 7,300 GWh -9,200 GWh . We have not even started in the renewable industry to compensate for non-renewable sources. We just take care of the growth. That even underlies a three-degree global warming scenario. If one had a two-degree global warming scenario, those needs would be even higher. Indeed, with global wind, Gurit is in a growing field of business. If you look at slide seven, I commented that to the biggest part already.
You see that pull-forward effect of the subsidies in 2020 and 2021, with 71 GW and 77 GW. A certain compensation in 2022 and 2023. The business goes on a high level from a 70 GW in 2024 to a 90 GW in 2028. I would also like to highlight that the volatility of those predictions are still relatively high. That could mean that the year 2021 may not exactly be 77 GW, may be a bit lower or a bit higher. Also when the levelized cost of energy are met with the non-renewable sources, 2022 and 2023 may not fall as deep as it is shown here. We have to take those installation data with the usual grain of salt. Moving on to slide eight. This is the management development in Gurit.
We have appointed today or announced the appointment today of Mitja Schulz as CEO of Gurit, and therefore my successor. We have earlier announced the arrival of Ernst Lutz, who is joining us on the 1st of September as a general manager of materials. Mitja joins us from Terex, which is exposed to wind energy with its products. Also Ernst Lutz had an exposure to wind energy earlier in his days when he was member of Alcan, and therefore had to do with composite materials and structural core materials. Ernst is a very techy person. Mitja is a general management expert. In our attempts to recruit 50% ballpark of the new leaders of Gurit from internal and 50% of the promotions from external. We also are very proud to repeat here that Lance Hill has been promoted to GM of marine and industry as of the 1st of May.
Lance was running before the Americas region in composite materials, including at that time, aerospace, marine and wind. Andreas Kipke has been promoted to GM Kitting as of February 2020. He is a long-term employee of the kitting crew in JSB, and we are very happy that he could take the leadership role of our kitting BU, which is a strongly growing business. On slide nine, we have the health and safety program, which is an important one for us. Gurit already has a high-class safety level, but we have set ourselves the target to reduce the accident rate on occupational health and safety by 50% in the years 2019- 2022, basically as of compared to 2019 in the years 2020, 2021 and 2022. That's 17% improvement on long-term absence rate caused by incidents or accidents per year.
I'm very happy that Gurit is on track with the program year to date 2020. We have undertaken big steps to improve here with the typical measures of the safety attentions, the safety walks, and the rigorous checkup on all conditions and situations which could cause incidents or accidents globally in one major effect. On sustainability, it's important that we are not only doing the right things, namely renewable energy and light weighting, but we also do it the right way. That means with the lowest climate impact, which is possible to run our business. I would like to highlight that Gurit, over the years, have taken already several steps. For instance, the launch of the new thermoplastic foams as compared to the thermoset foams.
Also our local for local footprint we are establishing, which means less transport from core material, which is in essence air, 10% material and 90% air, depending on the foam. Transport minimization of those products has a clear carbon footprint improvement trend. We are going to assess our footprint during the second half of this year, and we'll be formulating our expectations and ambitions still during this year, 2020. On the next slide, we have a quick summary of the chart of the sales development comparing 2019 and 2020, each the first half year. We can see that in the top left corner, the level in the continued operations of wind energy on total sales has further grown, over 80% now. In the regional sales, you could see that Asia Pacific had a vibrant development.
Americas was slightly down, Europe plus-minus stable, and the number of employees working full-time equivalent for Gurit has grown from 3,027 to 3,122. With that, I would like to go over to the key financial notes to which Philippe Wirth is going to give all the details to. Just here in terms of net sales growth. As you know, we have divested the automotive business, so the continued business is total minus automotive. In those numbers, in terms of sales growth, in reported Swiss francs, due to the automotive effect, we had a slight decline of 0.5%, but everything else grew by 2.3% in reported Swiss francs. You take the strengthening of the Swiss francs and therefore, the effect of consolidation in Swiss francs versus local currency into account. Even including the automotive divestment, the business grew 5.7% and 8.7% on the continued business ForEx adjusted.
If you look at the operating profit, we can say that the total business improved, including automotive, because last year we still had losses in that business. We grew from 9.7% to 11.1%. In the continued business, we were slightly down due to the tooling and the aero effects from 12.5% to 11.2%. Underlying, actually, we can say that the big achievement of Gurit has been that even if a higher margin business like tooling has, for whatever reason, a slight dip, the Gurit capability to keep the margins is improving because across the businesses, we have more sustainable margins. Those 11.1% for the total business compare to a guidance of 8.5%, including about a month of COVID-19 from our 9%-11% range we have given.
That 8.5%-11% guidance range was slightly overachieved at 11.1%, which is a very good result given all we underwent this year to date. A couple notes to the strategic investment programs. As I mentioned already, the wind energy market is growing. Blades are growing in size. Cost pressures are there. thermoplastic foams are expected to be the winner over the thermoset foams. The PET-G, therefore, as a thermoplastic foam, its share in the wind turbine generator blades is expected to rise. In 2020, about 30% of the material used in wind turbine blades were made out of PET. In 2023, we expect that share to dramatically grow to 70%. balsa PET are more or less the combinations of the future as we spoke.
This trend we foresaw and started with our investment program in this direction is accelerating, not only in the Americas or in Europe, but also now in China. Gurit's ambition is to have 30%-40% of that market share in PET, and for this purpose, we make a significant capacity ramp-up. We completed in the first half year 2020, our new China extruder number three. I come later to that because it's a special design made and designed by Gurit. We have the extruder in Mexico, the first line installing in the Americas region by quarter four. Under the difficulties of COVID, basically installation and the ramp-up of those extruders is not easy.
A lot of it we have to do with telecom means because the place where the knowhow around the equipment sits is not the place where the factory goes up. As a next step, we already communicated for South India. We are at the moment an importer of materials into India, and the Indian subcontinent has issued duties for materials and equipment to be imported into India of sizable nature to foster a local development of production. That South India extruder is planned to go live by quarter four 2021. On PET, as it becomes the major stronghold of Gurit in the core materials, we have undertaken a major investment program in innovation for cost out and properties improvement. You can expect lower cost per cubic meter of PET produced, and you can expect a lower density enabled by higher properties of the foam we design.
Last but not least, launch of the high-capacity extruder. CapEx and OpEx together form the basis of the cost per cubic meter of PET, so therefore, we have designed an own extruder category, which is higher in performance, lower in investment cost relative to lower performance extruders, and therefore, overall give a cost-out potential to the customer base, which is clearly a need of the market. If we go further on kitting, we have to ramp up the capacity very fast. You have seen the vibrant growth in our kitting business. The Gurit ambition there is also to have a 30%-40% market share in kits, means core machined to the exact shapes the customer needs to put in the blade. In essence, this is a service business from a characteristics point of view.
From technology point of view, we have finished the prototyping session of our next-generation kitting lines to be deployed as of 2021, which allow for higher automation in the process and also a higher output per CapEx and a higher output per machine and person involved. In terms of the capacity ramp-up, Mexico was in 2020 finished, started in 2019, and is now expanding further. North India, we will have a plant there by hopefully the end of this year, depending on COVID-19 and its development in India. We have also decided to set up a kitting co-located with a core plant, with a PET extrusion plant in South India, in the Chennai area in 2021. We will continue to expand the capacity we already have in China, but this one, especially for local OEMs operating in China in the Chinese market.
The Chinese market is the biggest wind market in the world, and we need more own presence and more own selling into the local Chinese customer base. If you look at the strategic programs on the next slide from a footprint expansion point of view, you clearly see Mexico 2019, 2020. China expansion and India expansion 2020 and 2021. These are the three geographic hotspots we are active to develop. In Mexico, there is still the extruder going live by the quarter four, as we spoke, depending on COVID, for the North American market. It's also located in a location whereby we can support the Middle American market and the South American market as the location is very close to the Gulf of Mexico.
In India, this is a program for 2020 starting, particularly 2021, and hopefully ending already in 2021 then. We are also there not so sure about the exact timing. The north kitting site will start in Ahmedabad, and then the south in the Chennai area will have three operations, a new tooling operation, a new extrusion of PET, and the kitting site, of which the extrusion and the kitting site will be co-located in clear proximity to the customers. In China, there is an added extrusion capacity in Tianjin 2020, which I mentioned already, and we will add kitting capacity more even in 2021.
You look at then at the business development in the units, that is the first one on composite material, which is still the combination of Wind and Marine & Industrial Materials, which subsequent to May, we are going to split out. That means Marine & Industrial Materials is going to be an own business unit. The sales of this business unit first half year grew at 9.7%, and at constant ForEx, 16.4%. That includes higher growth numbers in Wind and a little reduction in Marine & Industrial Materials as ingredients to it. We can speak of solid growth in the Wind Materials market.
We have also to say that the balsa cost we source and the balsa prices by which we sell it to the customers have been boosting revenues to a certain degree and have been altogether rather of a problem because of the stop-and-go availability of balsa, where we had customers with big demands, and we were struggling to deliver all which was required. Altogether, we can say that all our kitting and core material factories, particularly here, the core material factories, were running at capacity limits in 2020, first half year. In the other materials markets, marine and industry, I already covered that. We saw a slight decline in sales. What were the major steps in the first half year? We split up the wind and marine industrial. I already announced that and spoke about the organizational measures taken in Gurit in the first half year.
This is driven by the wish that we are a more market-focused organization in marine, that dedicated resources and a dedicated target market deliver, in general, better results than if you focus it across the commodity groups or you have more of a product group organization. The PET capacity expansion, the third extruder of the new type, was launched flawlessly in China. It was commissioned there, and we also took the investment decisions for the next extruder in South India. For second half year, it's about Mexico, bringing that extruder to life. On Balsa, it's the volume recovery due to the impacts we saw in harvesting wood under COVID in Ecuador, but also in Indonesia, and then raise the volume to the customer needs level. In Marine and Industry, this business unit is now operating since the 1st of May.
We will set sales initiatives with our integral marketing offering of core material, formulated products, and prepregs to sell on a higher level. That's the idea. We go further to kitting, we have a very dynamic growth of 47%, currency adjusted, even 57.1%. It is driven by clear volume growth, but also fueled by material cost and price increases. I already mentioned that on the balsa. There is a certain level of inflation in there, but this does not explain the result in full, of course. There is volume growth. The key business steps in the first half year, we have shown the capability of a global service organization to customers, particularly when they were on the stop-and-go phase. We could offer kits. If one location was down, we could offer it from the other.
As we have a global reach, that helped us to keep customers basically afloat, also in cases where a kitting organization in a certain country was affected by a shutdown. Here, in this stop-and-go phase, we could clearly prove that our operations at global scale had a significant competitive advantage over people who do only kitting in a region or only in a country. Which, when they are down, then that's game over for the time being. We have managed significant growth in the kitting team, and we also had to do many kit changes. As we spoke, the kits are changing from PVC, SAN, balsa, to combinations of PET and balsa. There's a lot of kit changes which the team has managed also in this year. We have the completion of the innovation of our next-generation kitting line, which I covered already.
Also, we have made the organizational staffing for the growth of the future around Andreas Kipke, his sales team, his operational team, the site location, startup teams he needs to build the new sites which we have in focus. For the second half year, the footprint expansion in North India and the preparation of the South India plant for 2021 will be the key topics, as well as the capacity increase for the Chinese business to grow. Let's move on to tooling. There we saw a decline of about 32.4%, and adjusted for currency, 27.8%. That's a negative result. It, however, compares to a very strong previous year, where we had a lot of high-value international orders. Whereas in the quarter 3 and 4 in 2019 starting, and quarter one and two consecutive, we have seen more Chinese orders, which have a lower value per mold system produced.
We have been shifting the business from the quarter one and two into three, four, into more the Chinese customer base. Therefore, those price value per mold system decreases explain, to a certain degree, the top line. However, in the quarter two, if we compare that one, we can also say that we consecutively grow back from quarter four, quarter one 2020 into quarter two, and we can say that the development will be more balanced. We expected a higher first half year 2020, and now we are seeing a more balanced full year 2020 overall. Moreover, under COVID, there was travel restrictions. We had difficulties of getting the customers to the plant to accept the mold systems. We had travel restrictions to install new molds, and that has had another impact on our top line in terms of delaying mold installations.
As well as we can say that one or the other international program has also been stopped, and customers regrouped and look at their situation again. Furthermore, we have made progress on the automation equipment. That means girder placement, shear web placement systems for those super long molds, but also mold data management and visualization. That is an undertaking to visualize and control the curing behavior of plates in molds in a more controlled and data-driven way. That will help the customers to assess the relative stage of curing, and therefore help to control and reduce the mold curing times. Particularly on big molds, this becomes an important matter that the customers can dynamically adjust and manage the curing profile of his product in the molds. Additionally, we have launched a new power hinge generation. Power hinges are equipment pieces which help to close the molds.
On the bottom right side, you see an open mold, and a hinge would help to close that mold. Actually, several hinges in a row have to precisely close that mold. We have installed and we have developed a more torque and optimized hinge generation to be launched in 2020 and 2021 into the market. What's up for the second half year in 2020? Obviously, footprint expansion India. We're going to open a tool shop in India, in South India in 2021. That needs to be prepared. Further innovation on the bespoke process automation equipment, so we can help to cost out and reduce cycle times. The last point is also industrial cost-out projects to produce the mold cheaper per square meter of mold surface. Those are the three key matters which are on the map for 2020 second half year, then ongoing into 2021.
Last but not least, aerospace. Well, aerospace has been hit real hard. You can see that on the visualization, top right. The first quarter was still a good quarter, and then the second quarter actually collapsed. That collapse has been driven by two factors. One is obviously the market reduction on new planes being built and sold, order cancellations at our end customers, but also a supply chain de-stocking. If the supply chain was stocked for a run rate of, call it CHF 13.4 million, for instance, in quarter one, if people expect a lower output, they need less working capital in process. Not only has our business reduced, but also the de-stocking took a special hit on the quarter two. What were we doing in the first half year 2020? We continue to modernize the Kassel site. We prepare for installation of a new prepreg tower.
We already did one a couple of years ago. The Kassel site will be basically operating out of new prepreg machines. We have the newest and latest technology installed. We accelerated the business transfer from Zullwil into Kassel. Basically bring the business of two plants into one in Kassel. That was foreseen originally in 2021 to happen, and we accelerated that due to COVID towards the end of this year. We had to do significant short works programs in Kassel and Zullwil, starting with the COVID impact, taking its toll, until the plant consolidation towards the end of this year is ready. We have basically two times half of the original business into a new plant, which they will then get a full utilized plant with new machines in Kassel.
Business focus second half-year, clearly the closing of that Zullwil plant in Q4 2020, the accelerated closing. Product innovations to support business recovery. Particularly as this recovery will be gradual and over several years, it's paramount important that we have business development actions joining the customers, helping the customers to get back on track and do our share of the work. With this, I will complete the update on the business units. I'd like to hand over to Philippe for giving you the details on the financials.
Thank you, Rudolf. Let me start quickly with a summary on the sales from what you have just heard from Rudolf. Material sales grew 16.4% in the first half, driven by strong wind energy demands. Kitting grew 57.1% with strong growth in China and Europe. Sales in the first half were slightly below the second half of 2019, mainly due to COVID-19, which temporarily affected us and our customers. Tooling declined 27.8% against a record result last year, and the continued shift to more China sales. However, our tooling sales have increased compared to the second half of 2019, despite temporary shutdowns of our plants in China and travel restrictions that hindered us to install molds. Aero was down 31.3% due to the sharp decline of the whole industry. In total, this leads to a 8.7% growth in constant exchange rate in our continued operation.
As a reminder, in 2019, we have bought a PET recycling operation in the second half of the year. When we exclude this, our sales grew organically 8.1%. Moving further to other operating results. Gross profit margin is 2.4 percentage points below prior year. The main drivers here were our tooling and aero business. In tooling, we continue to see fewer sales of high-content mold systems in the sales mix, as we focus more on gaining back market share in China. In aero, the reduction on gross profit margin is mainly due to the fact that we are not able to reduce fixed cost as fast as the sales volume have contracted. Here we have announced to pull forward the closure of our Zullwil plant into this year and react to this reduction, and we are on significant short work programs to mitigate the financial impacts on the business.
EBITDA is CHF 5 million below prior year, mainly due to the margin reduction in tooling and, as explained before, and lower sales in tooling and aero due to COVID-19. This could only be offset partially with strong results in materials and kitting. When we look at operating profit, I'd like to mention that the prior year number includes a CHF 2.5 million charge for our closure of the Zullwil plant. If we adjust this restructuring, our operating profit is CHF 5.4 million below prior year. On the next slide, we highlight some key reasons for this decline. Here we are looking at the key variances in operating profit of our continued business compared to prior year. As mentioned before, the prior year operating profit included a restructuring charge for the Zullwil closure of CHF 2.5 million.
Next, we have a negative impact on operating profit of CHF 1.3 million from increased material prices. Most of the material price increase we can pass on to our customers since we index our sales prices to raw material price changes, but some we can't due to various reasons, and we see continued pressure on the sales price in the Chinese tooling business. The net effect on operating profit you see here in this chart. Due to exchange rates, we have lost CHF 2.3 million of operating profit compared to prior year. This is due to the strengthening of the Swiss franc against all currencies in the first half year. Our reduction in operating profit includes strategic investments into our business, such as our health and safety program or improving our IT infrastructures.
This added up to an additional charge of about CHF 1.8 million compared to prior year. Overall, I would like to conclude that we are very happy with this solid operating performance of the first half year, which was at the high end or even slightly beating our expectations. Okay, now let's move on to cash flow. Free cash flow, which equals net cash flow from operation after capital expenditures, amounted to CHF 13.9 million in the first half year, compared to CHF 21.7 million in the same period in the prior year. This is a reduction of CHF 7.8 million. We have mainly two effects that contribute to this decrease. First, we have a lower profit adjusted for non-cash impairment charges compared to the prior year, and next, we have a negative impact of increased working capital as per end of June of CHF 4.9 million.
The working capital movement is somewhat volatile. It is particularly volatile in the area of trade account receivables around the cut-off dates for financial reporting. Also our customers are reporting at the same time as we do. Due to this reason, we look at the development of net trade working capital more on an average basis, on a longer timescale, and you see this on the left graph on this slide. We continue to see improvements of our net trade working capital requirements in the first half of 2020. This looks very good. This is mainly because of tooling with better payment terms with Chinese customers compared to the rest of the world. While we are suffering on sales and operating profit, we have benefits in the net working capital. Of course, the discontinuation of the automotive business has also helped us improving these statistics.
In general, we experience continued pressure to increase payment terms, which may hurt us going forward. The reason inventory levels at the end of June is to a large extent due to the supply chain disruption because of COVID-19, where on one side, customer orders were delayed or canceled, and on the other side, we were not able to adjust to the supplying side at the same speed. We expect this to correct itself by the end of this year. Capital expenditure amounted to CHF 11.8 million, and here I would like to highlight that 80% of the CapEx is related to capacity increases and dedicated to core material and kitting footprint expansions in China and Mexico. Capital expenditure for the full year 2020 is still expected to amount to around CHF 30 million-CHF 35 million, as we have guided before.
To conclude the financials, a couple comments on the June balance sheet. Net debt decreased by CHF 19.8 million from prior year to CHF 51.5 million this year. Our equity ratio improved compared to the prior year by 0.7 percentage points to 38.5%. The strengthening of the Swiss franc also had a significant impact on our balance sheet, as it reduced equity by CHF 12 million compared to prior year and reduced our equity ratio by 0.5 percentage points. Our gross debt to EBITDA ratio was 1.5 times, an improvement of 0.2 times compared to prior year. As a final comment, our return on net assets has improved 1.7 percentage points compared to prior year and is mainly due to the divestment of the automotive business.
In summary, we report a solid first half of the year given the economic environment. Our balance sheet builds a strong basis to continue on our organic growth plan. With this, I hand over to Rudolf for the outlook.
Thank you very much, Philippe. In terms of the outlook
Sorry, we can't hear you.
For the business guidance-
Go ahead, sir.
Thank you. For the net sales, Gurit adjusted a little bit the guidance. We said around CHF 600 million before. We now say CHF 550 million-CHF 600 million. That is due to Aero, the 50% consequential impact of the COVID, and the slight impact on tooling. So in that range. In the operating profit, we made a slide up from 8.5% to 9% to 11%, given the first half-year results and how we could manage the COVID impacts, particularly in wind energy. That leads me to the summary. I think my first and most important point is Team Gurit showed passion. We managed COVID as good we could. We helped our customers in an outstanding way, and that is the strength of a team, and I would like to thank my team particularly for this. This was really a challenging period.
It's not yet over, but the biggest part should be over now, and we did that well. We did the top management nominations and announced them and the organizational changes around marine and industry as we spoke. We showed strong business results for the first half-year, Gurit overall, with different results by different business units, but overall, a solid result. Aerospace was hit hard by COVID. The cost measures are taken and on the way, but the recovery will take several years to the level ex-ante. We continue with unchanged pace on our strategic capacity and footprint expansion on the wind sites in the geographies of Mexico, India, and more also in China. We completed the automotive divestment in February 2020, and we have set the new guidance as we spoke, CHF 550 million-CHF 600 million and 9%-11% of operating profit in our growth market, especially wind.
With that, I would like to complete the presentation and move on to the Q&A section after about a 30 seconds interruption. Thank you.