Distribution statistics for .net 3.5 Framework

I would like to know on how many end user pc's the .net 3.5 Framework is currently installed (in percent of course). So is there any reliable data source out there?

Thanks!

Chad

From stackoverflow

• Same question is here http://stackoverflow.com/questions/790499/where-to-find-net-version-usage-statistics (haven't found your question). Hope we will find together someone with large web logs at least.

  P.S. Not an answer, sorry, can't comment yet...