A recent report released by Google states that Jelly Bean adoption has grown to 28.4 percent of regular usage. Ice Cream Sandwich adoption is reported at 27.5 percent. With a plethora of new devices being launched into the marketplace, most recently from HTC and Samsung, the jump is not surprising as many users are upgrading their older devices running Gingerbread or earlier.
The stats also provide a better picture in regards to Android fragmentation. Although one must remember that with each offering of Android, regardless the version, each OEM will “customize“ the base offering to better advantage its hardware offering. An issue not gone unnoticed by developers.
Source: Android Dashboard