From NetMarketShare(TM) for June 2011: Operating System........ Total Market Share (top ten)- Windows XP........51.13%
- Windows 7.........27.13%
- Windows Vista......9.52%
- Mac OS X 10.6......3.78%
- iPhone.............1.41%
- Mac OS X 10.5......1.19%
- Java ME............1.12%
- iPad...............1.03%
- Linux..............0.95%
- Android 2.2........0.44%
All Windows versions together have over 88%. Mac OS X versions have over 5%.
Share of XP and Windows 7 only - over 78%.
(I guess statistics are about chosen websites and clients.)