From Upsdell.com, August 7, 2004:
Microsoft Internet Explorer: [b]Roughly 85% use IE-based browsers, down from a high of ~94% as users switch to other browser families - mainly Gecko - with this downward trend likely to continue as the alternate browsers improve and as IE remains stagnant with no planned upgrade for several years.
The article also notes that "The reported percentage of users varies a lot, likely in large part because many stats sources (a) are not properly identifying non-Netscape Gecko browsers, and (B) may wrongly identify Opera or Safari as a Gecko browser." Not to mention that many Opera users have it configured to identify itself as IE.
This will hopefully give a little different picture of reality to those who have been designing -- for years -- for IE only. The things to remember are two: (a) things change, and (B) correct coding should display correctly in all browsers.