The Extra Space Storage team took performance to new heights in 2021, with a record-breaking year in almost every area of the business. From innovative ways to invest capital in self storage to evolving our employee experience, our 2021 Annual Report covers some of the team’s efforts to innovate, implement, and grow. Here are a few highlights of how we grew and diversified our portfolio in 2021.
Extra Space Storage has over 2,000 locations across 41 states in the U.S. That equates to approximately 1.5 million storage units and 161 million square feet of rentable storage space. Our facilities offer a range of storage solutions, including climate control, drive-up units, auto and recreational vehicle storage, business storage, and more. Our ability to innovate technology and execute clean, well-lit facilities that offer a best-in-class experience for customers drove 2021 occupancy to 96.2%—the highest occupancy in our history.
Just 47% of our stores are entirely owned by Extra Space Storage. We have diversified our portfolio with joint venture holdings making up another 13% of the business, and the remaining 40% is managed on behalf of third-party owners. Because of this structure, we can make investments ranging from small purchases to more significant capital-intensive expansions. Additionally, we are able to have greater economies of scale, manage market concentration, gain more data points for our research, and build relationships with over 200 partner groups of varying sizes and locations across the country.
Creating such a diverse portfolio helps us reduce risk as we grow and adapt to market changes. We have over 1.2 million customers across all demographics of age, gender, and income renting self storage. We operate in 50 of the largest metropolitan areas and have a balanced presence in other markets of varying sizes. That balance means that no single metro area makes up more than 12% of our revenue.
Finally, our investment in portfolio diversity extends beyond acquiring new properties and partnerships. We have a comprehensive renovation and expansion program targeted at increasing net rentable square feet, improving visibility, and optimizing unit mix. These redevelopments make older structures more modern and appealing to customers and inject new life into the surrounding community with fresh on-brand design.
We are continually reviewing our portfolio to identify opportunities to invest in our properties today, that will help us improve our performance tomorrow, and in the years to come.