I think it's about 16 million, and perhaps there are 1200 faculty teaching full-time, with multi-year contracts, or tenure, or on tenure track; with salaries, health and retirement benefits, and so-forth.
Maybe I am wrong. But I'm not sure.
Here's an example of my problem. If I look, say, at the page marked "Employees," which you can get from the "Facts and Figures" page helpfully published by the Office of Institutional Research and Planning for Westchester Community College, which is one of the places where I ply my trade (teaching anthropology and related subjects), you will see that, under "faculty," are the numbers 164, for Full-time, and 2 for Half-time. Insofar as I teach at this same college—as an adjunct, and therefore part-time (there is a cap on adjuncts that prohibits us from working full-me)...and I know, well, more than two other people who do the same...that's already more than the 2 mysterious "Half-time" employees, so that can't be us, can it? And, insofar as there is, in "Facts and Figures," no report on adjunct faculty, well, that's a problem.
At the analogous page for LaGuardia Community College, where I also teach, I can see that 64% of faculty are accounted for as "part-time," which is the standard, and belittling, code for adcon faculty who, of course, are usually employed full-time—they'd better be, at 1/3 or less the payrate of "traditional" faculty—but not at one institution. But at least the reporting is fairly open.
And, let's see-at Fordham University, where I also teach, as a "part-time" adjunct (what else?), on the "Fordham Facts" page I read that there are 703 full-time instructors (41% are women, and 16% are minorities, in case you're interested—they do collect some info). 391 of these are tenured. By the way, you can also see that 95% of all faculty hold not a, but "the Ph.D. or other terminal degree." That the thing always make it sound like there's only one, doesn't it? Anyway, I hold a Ph.D. myself, and as a 20-year adjunct the difference between it and something "terminal" begins to seem trivial.
You see what I mean. Or not. Do you have something mysterious happening where you teach? Disappearing faculty? Percentages of full-timers approaching 100% Please let me know. Maybe I am missing something.