Version info on wikipedia:
http://en.wikipedia.org/wiki/IOS_version_history
Market share articles:
Summary from Instapaper, 8/13/2011
- 4.3: 82.5% use version 4.3 or greater
- 4.2: 96.0% use version 4.2 or greater
- 4.0: 98.4% use version 4.0 or greater
- 3.2: 99.0% use version 3.2 or greater
Summary from Bump app, 1/13/2011
- Binned by major rev:
- 4.x: 89.73 %
- 3.x: 10.25 %
-
2.x: 0.02 %
-
Individual minor revs:
- 4.2.1: 52.89 %
- 4.1: 27.50 %
- 3.1.3: 6.43 %
- 4.0.2: 3.36 %
- 4.0.1: 2.95 %
- 4.0: 2.94 %
- 3.1.2: 2.52 %
- 3.2.2: 0.49 %
- 3.0: 0.22 %
- 3.1: 0.21 %
- 3.0.1: 0.10 %
- 3.2: 0.10 %
- 3.1.1: 0.10 %
- 4.2: 0.09 %
- 3.2.1: 0.07 %
- 2.2.1: 0.02 %
- 2.2: 0.00 %