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.