It's actually showing that the number of staff has doubled over that time. If the staff in a school was always the smallest number, doubling it isn't as big a deal as doubling teachers or students. In fact adding on more staff that can help do things so the teachers can teach would seem to be a good thing. Additionally, using the term Administrative Staff can give the impression that we're talking about Principals, or School District type administrators, but Principlas and Assistants have their own category.