Google, like Apple, posts their mobile OS adoption rates. This one was updated on January 5th.

As you can see, Lollipop, Google’s latest rev of Android, is not even on the list. Kit-Kat, the version before Lollipop (Android 4.4) is at 39.1%. Jellybean (Android 4.1.x through 4.3) is, collectively, at about 46%. Lollipop is just not making a big enough dent to make the list.

It’s important to note that the Android data is gathered by monitoring checkins to the Google Play app store. In this case, the latest chart was built using checkins over a 7 day period ending on January 5th. A different approach than Apple’s, but it does give a sense of the numbers.

From the linked ExtremeTech article:

Slow adoption of Android is a fact of life, and things are still better now than they used to be. A slow start to Lollipop’s deployment isn’t the end of the world, and it doesn’t point to user discontent. Lollipop isn’t something people go out and buy, it’s delivered to them whenever an OTA is ready.

The Android distribution model is naturally fragmented (because different vendors ship their own custom version of the OS) and there are competing, forked versions of Android that are competing for adoption with the mothership (Samsung’s Tizen is a prime example).

As reported a few weeks ago, Apple’s numbers (as of January 5th) show iOS 8 at 68%. A world of difference.