Over 10% adoption of Mozilla?
According to W3Schools. While that's only 1/8th of IE-based browsers, that's still a significant chunk (more than IE5 browsers at least). XP was the fastest growing OS this past month (+1.3%), with Linux following in a distant 2nd (+0.2%). Although here's a quote from the page: "You cannot - as a web developer - rely only on statistics. Statistics can often be misleading. [...] Also be aware that many stats may have an incomplete or faulty browser detection. It is quite common by many web stats report programs, not to detect new browsers like Opera and Netscape 6 or 7 from the web log." They also include some notable statistics quotes.