Various other sources give much higher numbers, like up 179% from 1999 to 2020 [1] or up 110% from 1998 - 2018 [2]. So I'm not sure what's going on with the article. It could be that they're deflating by wage increases, or showing the change relative to overall inflation, or something like that.

[1] https://educationdata.org/average-cost-of-college-by-year

[2] https://www.cnbc.com/2017/11/29/how-much-college-tuition-has...

Edit: I would have assumed the OP article was based on this series: https://fred.stlouisfed.org/series/CUUR0000SAE1

This was the part that was most surprising to me as well. Most other reports seem to indicate that education is among the fastest rising costs compared to inflation, similar to healthcare. I'm surprised to see that number so low in this report.