Grad students outnumber coalminers 70:1, if they're roughly half international which another comment claims, that's still a big difference.

The way "coal miners" are discussed would also likely be something that puzzles historians. There are approximately 45,000 coal miners in the US, that's roughly equivalent to the combined enrollment of Harvard and MIT. There are more university students in the relatively small city of Cambridge, Massachusetts than there are people mining coal in the US and yet we have to pretend the latter are a constituency worth considering.