John Hawks notes that the number of full time faculty per college administrators has gone from 3 to 1 in the time period from 1975 to 2008 in the California State University system. "[T]he number of full-time faculty in the whole CSU system rose from 11,614 to 12,019 between 1975 and 2008, an increase of only 3.5 percent. In the same time period the total number of administrators rose 221 percent, from 3,800 to 12,183." In the same time period, within the category of college administrators, the "managerial and professional" category "has bloated extremely," while "clerical, service/maintenance, and technical jobs . . . have actually declined significantly over the same period."
I suspect that one missing piece of information that clarifies the picture is that the number of part-time faculty, and the number of graduate student instructors not counted as faculty, has ballooned, but I can't confirm that fact.