umm..h.264 is in IE8 and 9. The only browser that won't support it is Firefox.
http://marketshare.hitslink.com/report.aspx?qprid=0
Depends on were you are doing your counter. One I like to look at often will put a FF+Opera well over 30%.
Opera is not supporting h.264 either. So Opera+FF = around 25% of the market. so around 25% of the market i not supporting h.264.
Safari around 5% - the ONLY browser that is not going to be able to play WebM.
25 is a lot greater than 5