Also, it is interesting that Android 2.2 makes up the largest percentage of OS's out there in use.
Can't Android users upgrade to the latest OS? 2.3.3 is the latest phone OS.
I came across http://edovia.com/iosstats recently. Interesting to see how much iOS is fragmented (nothing compared to Android but still).
Obviously it is somewhat limited by being a sample. It would be nice to have something similar from Apple.