Rowing and squash (and other sports) were not included as not enough high schools sponsor teams in those sports and most go from a club team to a college team. The chart was measuring how many high school students go on to play in college. Even hockey is hard to measure as a lot of states don’t have a strong high school team pool, but do have club teams. A lot of high school hockey players go to boarding schools or play on the club circuit in other states.
We had 4 women’s rowers sign NLI but our school didn’t have a team, and there were two male rowers too, but that’s not an NCAA sport so they weren’t counted in either the high school stats or the college ones.