When did US undergraduate education become so expensive? As far as I know, in the majority of  countries in the world, especially in Europe, undergraduate education, even at the top universities, is almost always significantly less expensive than at prestigous US universities. 

For example, for the 2018-2019 academic year, the standard cost of tuition and fees at MIT was $51,520. Add in room and board and other fees, and the price tag reaches $70,240 annually. The average cost after aid was around $ 22,549.

At Cornell, the cost after aid was $30,498 and at NYU $37,362.

This is representative of most of the Ivy League schools as well as many liberal arts schools which are less well known internationally. 

The average tuition cost at my school in France is a mere 2000 euros per year whilst other French schools have tuition ranging from 300 euros per year to 15,000 in one extreme case. In several European countries, tuition is either free or students are payed to study. 

The student debt crisis in the US is a recent phenomenon, but how recent? I suspect that that students at Ivy League schools in the 1930's weren't paying anything close to their present counterparts, adjusting for inflation.

So when exactly did top tier American schools start raising  tuition and board fees to the astronomical levels we see now?  

I will leave out the question if whether this is sustainable or what the consequences will be, as this is speculative and opinion-based.
This article in USA Today from 2017 shows the graph below, which is average tuition and fees adjusted for inflation from '71-'72 to '16-'17.



To answer the question in the title: it looks like it started rising above inflation in around 1983.