Hello, I'm Andy Walters, Executive Chairman of Quartix. This is a short presentation of our interim financial results, which are available to download on our website. We started our company 23 years ago, and our target customers were SMEs, typically owner-managers, in sectors such as security, heating and plumbing services, landscape maintenance, construction, and other site-based services, just as they are today. The business information we provide to these customers is crucial to their operations. We provide a service to these customers on a subscription basis, and this has always been the case. In order to do this, we fit a small tracking device in each of their vehicles and provide them with operational reports through web-based and mobile apps, which help them improve their financial performance.
Typical benefits they achieve are increased capacity utilization, reductions in overtime payments, management of risk, reduced fuel usage, the elimination of fraud and wastage, and a reduction in their carbon footprint. This chart shows the continued growth of our subscription base since 2001, with key milestones highlighted along the way. A PDF of this presentation is available to download on our site. Geographic milestones include our launch in France in 2010, USA in 2014, Italy, Spain, and Germany in 2018-2019. Today, we have over 280,000 vehicles under subscription and 29,000 clients. Each month, we win more than 500 new clients. The business model we created is best illustrated by this chart. The segments at the bottom represent subscription invoicing to customers won before 2010, followed by each customer cohort since then.
At the very top is the part-year contribution from new customers won in the first six months of this year. Total represents 94% of our total revenues. This business model has stood the test of time and is based on high levels of repeat custom from existing customers as their fleets grow, which helps offset the effects of attrition. This year, for the first time, we made an inflationary price adjustment, and this has helped enormously in increasing revenue retention. Growth in our cost is largely based on wage cost inflation, as it is for our customers. We'll therefore look at whether an index linked to this might be more appropriate for any future adjustments. The importance of the reports that we provide, together with our reputation for outstanding service, ensures high customer stickiness, particularly with medium-sized fleets.
I'll just go through our financial performance for the first half of this year. Our total revenues were GBP 16.1 million, on which we achieved a gross margin of 69.2%. Our operating profit there was GBP 2.7 million in the six months. And as you will see in the interim results discussion, we incurred about GBP 0.6 million of non-recurring costs associated mainly with the operating costs and liquidation costs of the Konetik acquisition.
So, the GBP 2.7 million is stated after deducting those costs. Adjusted EBITDA GBP 2.73 million, earnings per share basic GBP 4.49, and earnings per share diluted of GBP 4.37. And free cash flow, excluding the capital cost of the Konetik acquisition, GBP 1.1 million. And again, that's after the exceptional costs that we incurred in the first half. I'm going to go through region by region now, rather quickly. Again, there's much more detail in the interim results.
Starting with the UK, the UK was the principal beneficiary of renewed focus on the company's core business following the termination of the Evolve product line. This led to 6% growth in annualized recurring revenues, a 7% increase in the subscription base, and a 17% increase in new installations. Notable successes were achieved in medium-sized fleets, where the company's reputation for strong customer service played a significant role. We continue to maintain a five-star rating on Trustpilot. A return to growth in the customer base, albeit at a modest level, was delivered in the period, and strong emphasis on increasing growth in customer acquisition rates is beginning to show positive results. In France, annualized recurring revenues and subscription base grew by 20% and 22%, respectively. Customer acquisition rates increased by 4% compared with the prior period.
New subscriptions were, however, flat on the same period last year, but 14% ahead of the second half of 2023. Good progress is now being made through all channels. In the USA, performance has continued to be adversely affected by organizational marketing changes made during 2022 and 2023. As a consequence, progress in ARR reduced growth from a positive contribution of £0.5 million in 2021 to a deficit of £0.2 million in 2023. Recruitment is progressing to support the U.S. business, return the subscription and customer bases to growth, and to return attrition rates to former levels. Inquiry levels are very encouraging, and customer acquisition rates are improving. In Spain, Italy, and Germany, our new territory, strong growth was recorded on all key performance measures in each of the countries.
The combined ARR, annualized recurring revenues of these three territories, grew by 54% to GBP 2.5 million on a constant currency basis. New customer acquisition rates in Italy were particularly strong, as was growth in new installations in Germany. All three countries offer substantial opportunities for business development, and further investment is planned for the second half of 2024 and into 2025. At the time of presenting our 2023 results and six months into my return to the business, I set out what our objectives, our principal objectives, to get us back on track were for 2024. This chart and these bullet points give some update on how we're doing with those objectives. Number one, really the top priority for me was to accelerate growth in the customer base.
One of the reasons I returned to the business was that the net rate of customer acquisition had fallen quite dramatically from a peak of just under 2,000 net customer additions per six-month period in 2021 to under 1,000, so it had halved. I'm very, very pleased to say that we have already achieved significant improvement in that with a 42% increase compared to the lows that we've seen over the last 18 months. Second point was to eliminate the cost of Konetik. This was an acquisition made in September of last year, just before my return to the business. It was an acquisition that had fairly significant operating costs but no revenue. That cost has now largely been eliminated, and the liquidation is well underway. We have taken a provision in our half-year accounts for the remaining cost of liquidating that company.
Third point was annualized recurring revenue to grow faster than overheads. And again, we're well on track with that, doing much better now. Fourth point, channel effectiveness and balance in fleet markets. We have become too dependent on one particular channel, and that balance is now really starting to improve as we invest in all of our channels. Manufacturing cost reductions, we should be able to introduce further manufacturing cost reductions in the fourth quarter and updates and enhancements to our user interface and our mobile apps. And we're already introducing and launching the early functions of that on our web-based app, and we'll be working on that with the rest of the applications from Q3 onwards. In summary, Quartix has a strong cash-generative business model with 94% recurring subscription revenues. We have a highly competitive product offering and an excellent reputation for customer service.
Renewed focus on Quartix's core business of vehicle telematics services over the last nine months is driving profitable growth in all markets. The outlook for the rest of the year is good, and the board now believes it will moderately exceed market expectations for revenue and profit as they were prior to the release of these results. And again, you can download that or see that on the RNS that we published on the morning of 29th of July. Thanks very much for your attention. And if you have any questions on this presentation or to do with our interim results, then please do email us at investors@quartix.net. Thanks very much for listening.