Google updates its developer page about Android platform version market share. From the latest data, we can find Android 4.0 and above system occupy around 25% of all Android market. But Android 2.3 Gingerbread still occupies over 50% of Android market.
From the above chart, Android 4.0 has 23.7% market share, the latest Android 4.1 JellyBean takes 1.8%, these two have 25.5% market share in total. But Android 2.3 Gingerbread alone still dominates the Android market, it takes 55.8% market share. Besides 2.3 and 4.0, the third largest is Android 2.2 Froyo, with 12.9% market share, followed by 2.1 Eclair, 3.0 HoneyComb,4.1 JellyBean.
The following chart shows the different Android systems share change from 1st April,2012 to 1st October,2012. Android 4.0.3 rises fastest.
Also, Google list share of different versions of Android system in different devices with different screen size, different PPI. You can go to Android developer website for detail information.
Reference : http://www.36kr.com/p/156831.html