I am looking for recent statistics for the current corporate
deployment of the workstation versions of Windows. For example, I found
the following figures in a 2003 article at:
http://news.zdnet.co.uk/software/windows/0,39020396,39118540,00.htm ,

Windows 95     14.7%
Windows 98     12.5%
Windows NT4    13.3%
Windows 2000   50.0+%
Windows XP      6.6%

See paragraphs 3 - 6 of the above link.

I am primarily interested in Windows NT, Windows 2000 Pro and Windows
XP Pro.  Statistics for the US is most important. Worldwide stats
would be good too.
Statistics breaking down deployment by corporate demographics (small,
medium, large businesses, private, government, etc) would be ideal.