Google released Android 2.2 Froyo about five months ago and it’s now installed on 33 percent of all Android phones.
According to data collected by Google, just over 40 percent of Android users are running 2.1 and about 26 percent are still running version 1.5 or 1.6.
So if you’re developing your Android applications for version Android 2.1 API level 7, your application will run on about 75 percent of Android devices.