Four months after Apple launched El Capitan, the OS powered 44.8% of all Macs, according to numbers published Monday by U.S.-based analytics firm Net Applications. That was an increase of about two percentage points from the month before.
Net Applications estimates operating system shares by tallying unique visitors to its clients' websites. In the absence of definitive data from Apple, that user share is one of the few proxies for real-world OS X adoption.
El Capitan's 45% -- of all OS X versions, not all personal computers -- was a smaller share than predecessors like 2013's Mavericks and 2014's Yosemite accumulated by the end of their fourth full month. By that point, Mavericks had garnered 45.3% and Yosemite an even more impressive 51.4%.
The comparisons have some wiggle room, however. El Capitan debuted on the last day of September, while Mavericks and Yosemite were released on the 22nd and 16th of October, respectively. Using complete months as a measuring stick gave Mavericks a 14-day head start over El Capitan, and Yosemite an 8-day jump.
By discounting those leads, Mavericks was actually slightly behind El Capitan around the four-months-and-one-day mark, but Yosemite easily remained ahead of its successor.
Almost a third -- 30.3% -- of the OS X-using audience measured by Net Applications continued to run Yosemite last month, while 11.3% stuck with Mavericks.
Older editions, which have dropped off Apple's unwritten security support list, accounted for 13.4%, signaling that more than one in every seven Mac owners ran an out-of-date OS.
The free El Capitan upgrade can be obtained from Apple's Mac App Store, and supports iMacs as old as mid-2007, MacBook Pro notebooks from late 2007 on and MacBook Air laptops from late 2008 going forward.