A lot of research institutions will have a greater number of graduate students than undergraduate students, as grad students are (supposedly) the focus of the organization - they're the ones who are training to be members of the academy after all!

A quick google shows that Yale has 7,357 graduate students enrolled for the 2020-2021 academic year. While the number of administrative faculty ballooning like this is absurd (one is reminded of the University of California system building a new billion dollar[0] campus _solely for administrators_), it makes more sense in the context of ~12,000 students, and ~5,000 faculty.

[0] - I don't recall the exact number off of the top of my head, all I can remember was that it seemed extravagant and absurd.