Quoted by Rob Pegoraro in the WP on 2/27/05: " The research firm IDC estimates that of the roughly 514 million paid-for copies of Windows on desktops and laptops worldwide at the end of 2004, almost 21 percent were the aging Win 95, 98 and Millennium Edition releases. Among the 19 million Mac OS desktop and laptop installations IDC surveyed, just about half were running releases predating Mac OS X."
At work I have 20 PCs running everything from W95,98,ME,NT3.5,NT4,2000Pro to XP, and the reason is they run other software costing 000's$, which would have to be upgraded if we switch OSs. At home, I have 3PCs running win98, Win98SE and they are 2+Mhz processors with good video cards, 512 Mb mem etc and so ATI and NVidia support is valuable to me.