Extremely in-depth study of what the distribution of in-use Android versions looks like. Some truly excellent graphs and plenty of text describing what the graphs indicate.

Highlight:

It’s clear that Gingerbread has disseminated into the market much more slowly than either of Froyo or Eclair. In fact, it took Gingerbread about 17 weeks longer to reach a version distribution milestone (10%, 20%, 30%) than its two predecessors. While it is too early to fairly judge ICS’s trajectory, it certainly appears to have started at a slower pace than did Gingerbread (more on that later). A seemingly endless string of devices entering the market with Honeycomb and few older devices being upgraded to ICS makes it unlikely that we will see the Android version distribution improve in the near term.