A group of security researchers claim 637 million web users surf the web with outdated Internet browsers:
Using data collected from Google Web searches and security firm Secunia, the researchers, Stefan Frei (of ETH, Zurich), Thomas Dübendorfer (Google), Gunter Ollmann (IBM ISS), and Martin May (ETH, Zurich), analyzed the browsers used in a new report (PDF). They did so in an effort to understand why so many recent attacks by criminal hackers have been aimed at the browser, and why those attacks have been so successful.
Overall the authors found that roughly 40 percent of users were using insecure versions of Web browsers. Among the least compliant were users of Internet Explorer, which currently dominates the Internet browser market.
The data was collected in mid-June 2008. The users were scattered among 78 percent Internet Explorer users, 16 percent Firefox, 3 percent Safari, and 0.8 percent for Opera. Of these, 52 percent were running the latest version of Internet Explorer, 92 percent for Firefox, 70 percent for Apple, and 90 percent for Opera.
The authors note that it has taken IE 7, the current Internet Explorer release, 19 months to gain only 52 percent of the entire Internet Explorer audience. Forty-eight percent of the users in the study were either using an old version of IE 7 or still had IE 6 installed.