Android Police has a fantastic article about the adoption of Android through the years complete with a really good chart. Make sure you click The Big Android Chart graphic for a good view.
This confirms something I think we all suspected, Ice Cream Sandwich adoption is moving really really slow. On the other hand Jean-Baptiste Queru seems to think this is normal.
With the Jelly Bean announcement most likely coming at Google I/O this year, I’d like to see this chart updated in 6 months, I bet it will still be depressing.