Google outs report of Android versions usage on different Android Devices. According to report newly launched Android 4.1 Jelly Bean now runs 2.7% devices. Along with Jelly Bean, Ice Cream Sandwich is now installed on 25% android devices which was earlier at 5.1%. Still making up the largest share is OS 2.3 Gingerbread with 54.2%, but a good sign is that it decreased in the last four weeks by 1.6%.
We are expecting that next time it will rose more fastly as Samsung is rolling Android 4.1 Jelly Bean to  various of its new devices especially Samsung Galaxy S3.
Source:Â Android Developers