If you browse the web often, you almost certainly have seen many Android fragmentation comments; interestingly enough Google’s latest numbers indicate Android’s latest versions are running on 90% of all devices. This number was produced earlier today, and says 9/10 Android phones are running Éclair (Android 2.1) or newer. FroYo controls the largest margin with 57.6 devices running that version of Android. Android 1.5 and 1.6’s margins are slowly getting smaller and hopefully everyone will soon be in 2.X margin and all fragmentation comments will rest.
Source (Android 2.1 and up now on 90 percent of all Android devices | Android Central)