According to this article:
http://calacanis.weblogsinc.com/entry/5574794258282236/
Here is the breakdown of the browser market:
Internet Explorer 6.x 53%
Firefox 18.16%
Safari 11.25%
Internet Explorer 5.x 4.07%
Mozilla 3.18%
Opera 2.50%
Netscape 7.x 1.42%
BTW Firefox users, there was an exploit released yesterday and requires upgrade to the latest version