The last time we checked out Google's Android Device Dashboard, penetration of the latest version had reached 1.8 percent of active hardware. A couple of months later and Android 4.1 / 4.2 Jelly Bean is accounting for more than 10 percent of devices that accessed Google Play in the last 14 days. The share of Android 4.0 Ice Cream Sandwich devices also grew to represent 29.1 percent of active hardware, and while 2.3 Gingerbread still has the largest slice, it slid below half to 47.6 percent. That means developers can more confidently taking advantage of the latest APIs, but while the environment is much improved over when the dashboard launched in 2009, those fragments still mean some hard choices on exactly what to target with apps. Hit the source link for a larger look at the current numbers.
Google Android 2.3
Google Android 4.0