PC Technician’s work load

As the agency I work for grows, so do the number of PC’s. I’ve added to my staff over the years but am now at a point where I am wondering how many computers can one technician support?

We support about 250 PC, located in 9 locations as far awayas 50 miles. All of our support is inhouse. All of the PC’s are Windows 95, 98,2000,XP.

So my question is, how many PC’s do your techicians support, What is a realistic number? And what tools do you use to make it easier?