Apple’s OS X Mavericks operating system is the fastest-adopted version to date. According to a recent analysis done by Chitikia, the OS has reached 40 percent of the Mac user-base. This level has been achieved in the five months since Apple made it available as a free upgrade in its App Store.

In comparison, OS X Mountain Lion was adopted by about 34 percent of users in a 14-month period since its initial release, showing that the rate of Mavericks adoption is over double that of Mountain Lion.

Apple’s new strategy of releasing OS X via the App Store as a free upgrade, somewhat mimics its iOS distribution strategy, which has resulted in the adoption of over 80 percent for iOS 7 in the first four months of its release.

However, while iOS is growing, there is a slight wedge that prevents these adoption rates from being directly comparable. When iOS updates are available, they are pushed to every applicable iOS device, whereas for OS X users have to log into the Mac App Store and make a purchase to install the latest upgrade.