Power Line's Steven Hayward posts the following chart, without identifying its source.
The gold bar represents growth in students. The blue bars represent growth in librarians, teachers, administrators, principals and asst. principals, support staff, instruction coordinators, guidance counselors, and instructional aides respectively.
Some growth in aides and counselors, and perhaps teachers can be attributed to mainstreaming. Handicapped students were formerly tracked to special ed. Some handicapped students have a full time aide assigned to tutor or assist them.
Administrative bloat is a problem throughout education, including higher ed. We don't reward efficiency in education and, unsurprisingly, we don't achieve it.