Android 4.0 Jelly Bean Now On More Than Half Of Devices

Android 4.1.x Jelly Bean is
now active on more than 50% of Android devices in the world. Last month, Jelly Bean sat just below 50% ; however, they have finally crossed that
illustrious mark. Another good sign is that Ice Cream Sandwich decreased last month, likely meaning many OEMs are pushing software updates to existing devices.

Note: Because this data is gathered from the new Google Play Store app, which supports Android 2.2 and above, devices running older versions are not included. However, in August, 2013, versions older than Android 2.2 accounted for about 1% of devices that checked in to Google servers (not those that actually visited Google Play Store).

Source: Android.com