IE: 56% Chrome: 20% Firefox: 16% Safari: 5%
IE versions are broken up as: IE6: 10% (= 5.6% absolute) IE7: 25% (= 14% absolute) IE8: 65% (= 36% absolute)
In other words, dropping IE6 support is not yet plausible. But we've already opted to provide only functional support for IE6 - i.e., things need to work in IE6, and not look totally broken, but they don't have to look great.