There's several things to consider when looking at browser percentage for your site.

Site audience plays a large role.  Businesses tend to be IE-only.  Home users are strongly IE, with a mix of Firefox and some Safari.  Students are more diverse.  Web developers are probably the most diverse.

Also, site design plays a role.  If your site breaks in Firefox, many Firefox users will switch to IE or "switch to IE" (via User Agent Switcher.)

I'd be interested to see the user-agent statistics for Channel 9.