Android Gingerbread running on 50% of Android devices
From the chart we get to know that Android 3.X Honeycomb which was released specially for tablets only covers 2.5% of all the Android devices which is indeed less. Android 2.2 Froyo is still active on over 35% of the devices. While Android 1.X is still running on about 2% of all Android devices but its extinction is sure.
With the release of Android 4.0 Ice Cream Sandwich, it is sure that Android 2.2, 2.3 and 3.X will surely see a downfall as ICS has been designed to run on both mobile phones and tablets.