put in "Public Domain"
It's not clear to me, but R is distributing it without license statement

As alternative we could switch to http://www.econ.uiuc.edu/~roger/research/intro/  which is based on a public survey and used as example by SAS who cite Koenker and Hallock (2001) “Quantile Regression: An Introduction,” Journal of Economic Perspectives, 15, 143–156.

I didn't check if it has a similar structure. The Koenker Hallok dataset is large, 198377 observations, SAS uses 50,000 randomly drawn observations