According to OneStat (Amsterdam) the following make up most of the browser market:
1. Microsoft IE 6.0 46.4%
2. Microsoft IE 5.5 23.9%
3. Microsoft IE 5.0 23.6%
4. Netscape Navigator 4.0 1.4%
5. Microsoft IE 4.0 1.2%
6. Opera 6.0 0.6%
7. Netscape Navigator 3.0 0.5%
I remind you that Netscape was by far dominant to Internet Explorer before AOL/Time Warner bought them out.
Mozilla and Opera notice slight increases, but all non-IE browser increases don't add up to the 1.7% increase for IE 6.0.
Here is CNET's news.com article.