I think there is something to be said about provenance of the degree. For example there's been quite a lot of expansion in number of colleges or even community colleges expanding their systems while actual prestigious colleges themselves have only expanded so much.
Here are the stats for Harvard enrollment of undergrads (1,3), along with US population (2,4) and percent Harvard student (not sure where I get number of people in the workforce with harvard degrees data but maybe this is a decent proxy):
Year - ugrads - US population - % of US pop at harvard
Here are the stats for Harvard enrollment of undergrads (1,3), along with US population (2,4) and percent Harvard student (not sure where I get number of people in the workforce with harvard degrees data but maybe this is a decent proxy):
Year - ugrads - US population - % of US pop at harvard
1990 - 22,851 - 248,709,873 - 0.0092%
2000 - 24,279 - 281,421,906 - 0.0086%
2010 - 27,594 - 308,745,538 - 0.0089%
2025 - 24,519 - 343,000,000 - 0.0071%
1. https://nces.ed.gov/programs/digest/d13/tables/dt13_312.20.a...
2. https://www.census.gov/data/tables/time-series/dec/popchange...
3. https://www.harvard.edu/about/
4. https://www.census.gov/popclock/