Average expenditure per student:
Instruction: $17,996
Student Services and Academic Support (Not all of which are administrators): $9528
That results in $0.52 spent on Student Services and Academic Support for each $1.00 spent on Instruction. In 1999, that number was $0.47 spent on Student Services and Academic Support per $1.00 spent on Instruction. That's not a huge increase in administrators.
https://nces.ed.gov/programs/digest/d17/tables/dt17_334.30.a...
The cost of college is largely driven by reductions in state support for public institutions, and the resulting increases in tuition by both private and public schools:
https://fivethirtyeight.com/features/fancy-dorms-arent-the-m...
This page offers a summary of what that classification includes and it includes some clearly essential activities:
https://www.wisconsin.edu/financial-administration/accountin...
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