I would suggest that staffing requests be documented with usage of your
particular facility. For example, I have a simple electronic counter at
our entry that monitors how many (about 400,000/year) people going in
and out.  I also track pages of printouts(about 1.3 million).  I also count
access to our academic websites (about 200,000/year).

And then, of course, there is the matter of facility hours (101 hours/week
during the semester, 120 hours the week before finals), number of computer
workstations (100), adaptive technology support, etc.  The University's
population itself is 5,000 grad, 5,000 undergrad.  Academic Counseling
and the Writing Center are separate services not located in our facility,
although the Computer Competency Program for every undergrad
is taught and tested in my Center.

My staff includes 3 part-time(one .9, two .5) professionals, 12 workstudy
students, and one shared network administrator, and myself (full time).

Hope this helps... I would be interested in others stats, especially what is