StopBadware.org has released their May 2008 Infected Sites Report(PDF). They took their current list of 213K active badware websites and resolved the IP addresses. These addresses were used to determine the network block owner and country. The results could be skewed to networks Google scans more often, but they should give a decent overall picture. China hosts 52% of all the badware sites while the U.S. has 21%. There weren’t any other countries maintaining over 4% of the total. They also calculated the number of infected sites per capita, which China also led. Last year’s report resulted in several AS block maintainers cleaning up to the point that they don’t even make the top 250 this year.