Source: GoSquared
Yosemite launched on October 16, 2014, and early signs indicated a slightly faster adoption rate than Mavericks, the former leader. Yosemite has continued its relatively rapid pace, reaching just under 50 percent less than three months after its release. By comparison, Mavericks had an adoption rate of about 37 percent by the end of December 2013 and OS X Mountain Lion sat at just 26 percent during the same relative timeframe.
Looking at it another way, it took Mavericks 4 full months to reach a 50 percent adoption rate, and 12 months for Mountain Lion to hit the same marker.
Contributing to OS X Yosemite’s fast adoption rate was the operating system’s public beta program, which gave non-developers access to early Yosemite builds months in advance of its public launch. Net Applications calculated that about 4 percent of Macs were already running some version of OS X Yosemite on the day of the operating system’s public launch.
Another factor is Apple’s relatively minimal system requirements. OS X Yosemite can run on all Macs that supported OS X Mavericks, that is, all iMacs and MacBook Pros since 2007, MacBook Airs and Mac Pros since 2008, and Mac minis since 2009.
Of note, Apple’s penchant for hardware quality may be a problem, with millions of Mac owners still running their older systems. Net Applications reports that nearly 20 percent of Macs are running a version of OS X that is no longer supported, leading to potential security issues and precluding these users from accessing the latest apps and features.
Yosemite's rapid adoption numbers underscore the success of Apple's 'free update' model that the company introduced with the launch of Mavericks. With Microsoft set to release Windows 10 later this year, many are watching to see if the Redmond company will adopt a similar consumer release model for an operating system that his historically been relatively expensive.