Android 4.x now almost 40% of the ecosystem
4.2 (aka Nexus devices) saw a more modest increase this month after doubling its share last month, up from 0.8% to 1.2%. Android 4.0 Ice Cream Sandwich also saw a slight increase from 27.5% to 29.1%, putting the total for Android 4.x at 39.1%.
Android 3.x Honeycomb didn't see any change at all, but all older versions of Android saw decreases with Android 2.3 Gingerbread seeing the biggest drop and finally falling below 50% of the market to 47.6%. Of course, even though it has dropped that much, Gingerbread still makes up the biggest chunk of the Android ecosystem.
source: Android Platform Versions