The study, authored by ETH Zurich, Google, and IBM, examined the Google logs of users browsing the Web between January 2007 and June 2008, and tried to determine which users were using the most recent, patched version of their respective browsers. No personal information was collected, the study's authors said.
What they found was that most users – 52.4 percent – who surfed with Internet Explorer had failed to upgrade to IE7, considered by Microsoft to be the most secure version.
I agree, for totally selfish reasons. As a web developer I am tired of hacking CSS to support IE6. Get an upgrade people!