The faster your site, the more sites that are slower...
According to this Graph (based on Google's Site Performance) almost all sites are slower when your performance is 0,3 seconds.
% slower sites = 105 - 18 * site performance
Update 05-04-2010: At a regular base, I upgrade this graph, normally, it are minor changes. However today it seems that there is a real change in the graph (1.0s goes from 89% slower to 93% slower). The mentioned formula is not valid anymore.
Update 12-04-2010 From lifehacker.com I learned that at 1.4s 87% of the sites are slower (this was originally 81%).
Update 05-04-2010: At a regular base, I upgrade this graph, normally, it are minor changes. However today it seems that there is a real change in the graph (1.0s goes from 89% slower to 93% slower). The mentioned formula is not valid anymore.
Update 12-04-2010 From lifehacker.com I learned that at 1.4s 87% of the sites are slower (this was originally 81%).