“The price of textbooks increased by 90 percent from 1998 to 2016, according to the American Enterprise Institute.”
Yikes! What a racket! (Especially when you consider that there are a lot of fields that don’t change very fast and where old textbooks (sometimes very old) will do just fine.) For details on this racket, see www.chronicle.com/article/Hard-Copy-or-Electronic/244425.