Good morning, and thank you for joining us. We're glad to be back at CAGNY and hope that very soon we will be able to do this in person. I'm joined today by Sal Mancuso, our Chief Financial Officer. Murray Garnick, our General Counsel, who also leads the regulatory affairs organization, will join us for the Q&A session. Before we begin, we ask that you carefully review the safe harbor statement in today's presentation and the forward-looking and cautionary statements section in today's press release. These documents are available on altria.com, along with the reconciliations and further explanations of the non-GAAP financial measures we will discuss today. Future dividend payments and share repurchases remain subject to the discretion of Altria's board.
All references in today's remarks to tobacco consumers or consumers within a specific tobacco category or segment refer to existing adult tobacco consumers 21 years of age or older. Altria is advancing our vision to responsibly transition adult smokers to a smoke-free future. In this respect, we are aligned with tobacco consumers and the FDA, and we intend to lead the U.S. in moving beyond smoking. It's an ambitious goal, but one we believe will benefit tobacco consumers, Altria's businesses, our shareholders, and society. Corporate responsibility has long been integrated into our practices and strategies. Last year at CAGNY, we shared the results of our latest materiality assessment regarding the most impactful environmental, social, and governance issues that we believe we must continue to address.
We described our six corporate responsibility focus areas, and that the materiality assessment overwhelmingly affirmed that harm reduction and preventing underage use are the most important social issues for our company. Our harm reduction and underage use prevention efforts, specifically are woven throughout these remarks as we discuss our progress toward our vision. My remarks today will focus on the investments we're making in support of our vision. As outlined last month in our fourth quarter earnings release, we are investing to deepen our understanding of U.S. tobacco consumers and our digital engagement, increase smoker transition to our end market smoke-free products, and accelerate smoke-free product research, development, and regulatory sciences. I will update you on our progress and further details on each of these areas.
Sal will discuss the total tobacco landscape, how our traditional tobacco businesses continue to support our strategies, and our accomplishments in other ESG areas. Finally, I'll return for some closing remarks and for CAGNY participants, we'll advance to our question and answer session. Our vision begins with the tobacco consumer. There are approximately 50 million tobacco consumers in the U.S., and 33 million of them are cigarette smokers. We've analyzed nearly 3 years worth of tobacco consumer purchase data. The data show that almost a third of smokers have tried smoke-free products, but only 11% continue to purchase these products after 5 weeks, and only 7% of smokers continue to purchase after 18 weeks. These facts indicate that smokers continue to be open for smoke-free products, but many of the products they try fail to meet their needs.
We believe this is largely due to unsatisfying product experiences or inadequate consumer support during their smoke-free transition process. For harm reduction to succeed, we believe smoke-free products must meet consumer expectations and deliver enjoyable sensory experiences and nicotine satisfaction, reduce health risk, and clear authorized information about the benefits of switching, and the ability to avoid social friction associated with cigarettes, such as smoke odor, ash, and feelings of isolation. To better meet these expectations, we developed a holistic view of the smoker and their journey in switching to smoke-free products. It blends behavioral science and research on consumer lifestyles and behaviors, usage occasions, and product requirements, barriers and motivators for switching to smoke-free products, including information needed to make an informed choice, and current and preferred channels for purchasing and engaging with tobacco products, including the pre-purchase touch points that impact awareness, interest, and consideration of smoke-free products.
With our deep understanding of the smoker mindset, we believe we can more effectively and equitably transition smokers to less harmful alternatives. A major point of engagement for smokers is linked to their shopping behavior. There are approximately 25 million U.S. tobacco retail transactions each day. Tobacco consumer shopping behavior is highly routine, with 75% of consumers purchasing their products at a single preferred store. U.S. tobacco volume is sold about evenly across rural and metro areas. Thanks to years of building mutually beneficial trade relationships, our sales force has vast coverage across all these areas, servicing over 200,000 stores, which represent more than 90% of U.S. tobacco industry volume.
Our relationships with our retail trade partners serve several purposes, including supporting responsible retailing and efforts to limit the reach, access, and appeal to unintended audiences, and engaging with smokers in a key setting to apply our consumer insights and support our tobacco brands. While responsible point-of-sale merchandising has long been a primary marketing tool for our tobacco companies, digital engagement is becoming increasingly important. In fact, based on our research and experience with IQOS, digital channels are now the leading source of awareness for new tobacco products among tobacco consumers. Many of our top retail partners use their digital platforms to build consumer engagement and shopper loyalty. Based on our estimates, there are millions of tobacco consumers actively engaging on these platforms, and we expect this number to increase as retailers advance their digital efforts.
We expect our investments in this area to continue our support of responsible retailing, further solidify our trade relationships, enhance our data analytics capabilities, and further evolve our marketing to accelerate smoker transitions to a smoke-free future. Last year at CAGNY, we discussed a retailer incentive program for in-store age validation technology as part of our comprehensive approach to underage tobacco use prevention. I am proud to say that it has now been installed in more than 104,000 stores with an additional 36,000 stores in progress. We expect to continue our work with retailers to broaden age validation technology across more stores. This year, we introduced incentives for retailers to include age and identity verification solutions in their digital platforms. Once a consumer is verified, retailers can then provide personalized offers and messaging from our brands within the retailer's app.
At introduction, consumers can receive offers from our smokable and moist smokeless tobacco brands. Going forward, we expect to expand the program to include on! and other smoke-free brands. Our sales force is working with our retail trade partners to implement these solutions, and we expect approximately 30,000 stores will have these capabilities by year-end. We believe this seamless integration will allow us to better engage with digitally connected tobacco consumers, improve the strategic allocation of our promotional resources, and create infrastructure to support trial and awareness for smoke-free tobacco products. Finally, we believe our digital investments will provide incremental data to help us better understand each smoker's journey. We're creating a unified and real-time consumer identity that ties their purchase data and interactions with our brands to our marketing communications.
We believe that by using our tobacco consumer understanding and data analytics, we can recognize how an individual consumer is progressing towards smoke-free products, adapt our marketing approach, and better support their transition. We're seeing early success from applying these insights, which brings us to our next investment area and our progress advancing smoke-free products. In the U.S., there are now 1.5 million oral nicotine pouch consumers, and the category primarily attracts smokers and dippers. In fact, consumer purchase data show that relative to other cigarette brands, Camel and Natural American Spirit smokers repurchased nicotine pouches at the highest rate. In the fourth quarter, the oral nicotine pouch category reached a total oral tobacco retail share of 17.9 percentage points, growing 7.4 share points year-over-year. The category has developed at different rates across the U.S. based on timing of product introductions.
It is most established in the Western region of the country, where it increased almost 10 share points throughout the year, reaching a total oral tobacco retail share of 30 percentage points in the fourth quarter. on! made significant advances once Helix reached unconstrained manufacturing capacity. At the national level, on! almost doubled its fourth quarter retail share of the nicotine pouch category to 21.6%. In each of our sales regions, on! advanced at least 7.5 share points. In the Western region of the country, where Zyn had a significant first-mover advantage, on! more than doubled its retail share of nicotine pouches over the same period, reaching a 15.4 share in the fourth quarter. We are excited about the performance of on! and the opportunity for future growth to be fueled by our understanding of the smoke-free transition process.
For example, the Helix team uses its understanding to inform promotional strategies for on!. We believe this approach has allowed the team to consistently increase product trial and repurchases. In the fourth quarter, trial of on! increased approximately 5 x, and repurchases tripled when compared to the year ago period. We're encouraged by these results and the brand's appeal to a broad set of tobacco consumers. Our data show that on! sources more from cigarette smokers than Zyn. Roughly 60% of on! consumers are aged 21-39, a higher percentage than in the cigarette and MST categories, and approximately one-third of on! consumers are women. In comparison, women represent approximately a quarter of Zyn consumers and just 5% of the MST category. Based on our research, on!
Consumers appreciate its clear departure from the MST category associations, differentiated packaging, smaller pouch, which provides a more comfortable product experience, and taste and flavor, which they prefer compared to competitive products. We believe the breadth of the on! portfolio is a significant competitive advantage, supported by the balanced distribution of on! volume across flavors and nicotine strengths. As you are aware, the pre-market tobacco applications for the entire on! portfolio remain pending with the FDA. Previously at CAGNY, we've shared some of our research that provides strong evidence of on!'s ability to transition smokers away from cigarettes. Consumer purchase data and qualitative research further support that on! appeals to smokers. For example, a former smoker has described on! as, and I quote, "The first pouch I tried, and the one that inspired me to replace cigarettes," end quote.
Based on the data we provided in our PMTA submissions, we believe the FDA should determine that the marketing of these products is appropriate for the protection of public health. Additionally, we're preparing modified risk tobacco product applications for on! and expect to submit them to the FDA by the end of this year. As we learn from our experience bringing IQOS to smokers, MRTP claims can provide an impactful point of differentiation for brands and be an important tool for educating and ultimately transitioning smokers to smoke-free alternatives. For the on! applications, we developed claim communications supported by science that we believe will motivate smokers to transition to on!. We tested our proposed on! MRTP claims to evaluate consumer understanding and the effect on consumer use intentions. For current smokers, viewing the claims resulted in a statistically significant increase in their intention to try and use on!.
Importantly, the majority of both tobacco and non-tobacco consumers indicated that they correctly understood the claims and were not misled to believe the product was without harm. The proposed MRTP claims did not increase use intentions among non-tobacco consumers or decrease intentions to quit among current smokers. We're excited by these results and believe they demonstrate the importance of taking both a consumer-focused and science-based approach to tobacco harm reduction. Turning now to the other smoke-free categories. We made steady progress building the heated tobacco category in our early IQOS markets by educating smokers about the social benefits of heated tobacco products, supporting smokers on their journey to IQOS, and once authorized, communicating the reduced exposure claim to smokers. We demonstrated improved performance in each successive market.
Unfortunately, PM USA had to remove IQOS from the market in November due to the International Trade Commission's importation ban and cease and desist orders. We stand ready to bring IQOS back to market when the product is once again available to us. In e-vapor, our minority investment in JUUL remains subject to a challenge by the Federal Trade Commission, and JUUL is awaiting FDA decisions on its PMTA submissions. We continue to believe that a responsible, regulated e-vapor category consisting of authorized products can play an important role in harm reduction. We expect to vigorously compete in the major smoke-free categories through our investments, licensing agreements, and tobacco operating companies.
We believe it's important to have multiple products in these smoke-free categories to help smokers transition away from cigarettes, which brings me to our investments to accelerate smoke-free product research, development, and regulatory sciences. Investors frequently ask about our product development system and how it is different compared to 5 years ago. Let me explain why we believe it's stronger today. First, as I discussed earlier, meeting tobacco consumer expectations is critical to our success, and we now receive more data on their preferences, purchasing patterns, and friction points with existing products. Second, we embed our regulatory sciences team early in the process to help develop products that are aligned with FDA expectations for risk to the individual and the population. Third, we are committed to internal development with more focused resources, supporting consumer research, product design, and science.
In 2021 alone, we conducted more than 40 consumer research studies involving thousands of tobacco consumers and performed more than 15,000 scientific analyses on prospective smoke-free products. As a result, we have developed several encouraging products in the oral and heated tobacco categories. We expect to finalize designs for 2 of these products by year-end, and then begin regulatory preparations. We are excited about our pipeline, and we expect to share more at the appropriate time. We believe the tobacco harm reduction opportunity remains in front of us. We're continuing our efforts to work with regulators, legislators, the public health community, and other stakeholders to create the conditions necessary for harm reduction to succeed in the U.S., and we're making the investments in our businesses to lead the way.
I'll now turn it over to Sal to provide more detail on the business environment and our financial performance.
Thanks, Billy. I'll begin by sharing our view on how the tobacco space has evolved over the past several years. When we equivalize volumes across categories, we estimate that over the past 5 years, total domestic tobacco industry volumes has declined by less than 1% on a compounded annual basis. Smoke-free categories, such as oral tobacco and e-vapor, have become a larger portion of tobacco volumes, representing approximately 24% in 2021. In the cigarette category, 2020 and 2021 were dynamic years due to the external environment and its effect on smoker behaviors. As a result, we believe it's more insightful to analyze cigarette volume trends over the longer term. When averaged, the past 2-year adjusted cigarette industry decline rate was at 3%, well within the range of historic norms.
Looking ahead, we're monitoring factors that we believe may influence all tobacco consumer behavior, such as economic challenges, including inflation and the impact of the COVID-19 pandemic. While these factors present challenges, we believe that our businesses have the tools necessary to adapt appropriately. Our smokable product segment continues to generate significant cash for shareholders and to invest behind our vision. Our smokable product strategy is to maximize the profitability of our combustible products while appropriately balancing investments in Marlboro with funding growth of our smoke-free portfolio. Over the years, this segment has been resilient through various dynamic periods, such as accelerated volume decline rates, excise tax increases, and economic variability.
Over the last 5 years, our smokable segment grew adjusted operating companies income from $8 billion to $10.4 billion, representing a 5.5% growth rate on a compounded annual basis, and adjusted OCI margins expanded to 57.6%, an increase of 9.6 percentage points. Since the pandemic's beginning, Marlboro's share of the total cigarette category has remained stable while the share within the premium segment has increased. In the oral tobacco product segment, our strategy is to maximize profitability over time in traditional MST through the strength of Copenhagen and to responsibly and rapidly grow on! oral nicotine pouches. The segment continues to deliver robust adjusted OCI margins at more than 60%, while also making investments behind on!. Copenhagen continues to be the leading oral tobacco brand, and on! is performing well within the fast-growing oral nicotine pouch category.
Turning to our financial profile, we have a strong balance sheet and highly cash-generative businesses, which provide flexibility to our capital allocation approach. We've steadily reduced our leverage, which as of year-end 2021, stands at 2.3 x debt to EBITDA, down half a turn following our debt issuance in the first quarter of 2019. Of course, our investment in ABI also supports our balance sheet. At the end of last year, our ABI investment had a carrying value of $11.1 billion. We view our ABI stake as a financial investment, and our goal is to maximize the long-term value of the investment for our shareholders. In 2021, we returned over $8 billion in cash to our shareholders through both dividends and share repurchases.
Over the past 5 years, we've returned more than $36 billion in cash and grown our dividend by 8.1% on a compounded annual basis. Last year, we continued to reward our shareholders by raising our dividend for the 56th time in the past 52 years. We maintain our dividend payout ratio target of approximately 80% of adjusted diluted earnings per share. We're in the midst of our $3.5 billion share repurchase program. At the end of last year, we had approximately $1.8 billion remaining under the expanded program, which we expect to complete by the end of this year. Turning to our guidance, we reaffirm our 2022 adjusted diluted EPS guidance of $4.79-$4.93.
This range represents a growth rate of 4%-7% from a 2021 adjusted diluted EPS base of $4.61. We expect 2022 adjusted diluted EPS growth to be weighted toward the second half of the year. Before turning it back to Billy, I'd like to expand upon the ESG progress he mentioned in his opening remarks. I am proud to cosponsor our environmental steering committee. We recently committed to a long-term, renewable electricity purchase agreement that we expect to be operational by the end of the year. We believe this timing would allow us to hit our 2030 renewable electricity and operational greenhouse gas reduction targets 7 years ahead of schedule. Additionally, we demonstrated our commitment to understanding climate change risks and opportunities by publishing our first standalone Task Force on Climate-related Financial Disclosures report.
Another important focus area for us is supporting our people and communities. We continue to make progress toward our inclusion and diversity aiming points, including our goal that employees of color represent 30% of our leadership positions. At the end of 2021, employees of color represented 24% of vice presidents and 26% of director-level employees. In our communities, we developed a new 5-year community impact plan to drive business and social impact in several areas, including economic and workforce equity. We are extremely proud of the results our employees delivered in each of our ESG focus areas, and we continue to collaborate with our stakeholders on these critical topics. I'll now turn it over to Billy for closing remarks.
Thanks, Sal. I'm optimistic about the future for tobacco harm reduction in the U.S. There is a significant opportunity to shift millions of smokers away from cigarettes. As the leader in the U.S. tobacco industry, we believe we are best positioned to lead the tobacco harm reduction opportunity for several reasons. We have demonstrated commitment to responsibility and a robust understanding of tobacco consumers and the U.S. tobacco market. We have long-standing relationships with retailers and wholesalers, and a broad portfolio of products and investments across the most promising smoke-free categories. We have strong regulatory capabilities and a science-based approach to tobacco harm reduction. We have significant cash flows and a flexible balance sheet to support our investments and returns to shareholders.
With these in mind, and the hard work of our talented employees, I am confident we can achieve our vision to responsibly transition U.S. adult smokers to a smoke-free future. Thank you for your time and your interest in Altria.