I just had a look at the statistics for visitors to this blog, for UK colleges. The answer appears to be nearly a quarter now. The table is the last month’s visitors.
Although I don’t believe that it means that a quarter of all college computers are running Windows 7, I do believe it is representative of IT staff in colleges. And they’re probably already planning whether they are going to roll out Windows 7 to the rest of the college at Easter or in the summer.