Last Updated: April 30th, 2012

Pop quiz: How long does it take for a new version of Android to be widely adopted? A new version of Android comes out, AOSP updates, OEMs adapt it to a myriad of devices, and carriers test the updates. That process. How long does it take?

It's a tough question to answer, mostly because Google doesn't provide data like that. The official site shows a 6 month version history, and that's it.