Just some back of the envelope math: back in my day there were 15 individual track and field (outdoor) events, if we assume that states have, on average, 2 T&F divisions, we're looking at at lease 1500 individual girls state track and field champions every year.
A little over 3% of high school students are trans, so if the playing field were even between cis and trans girls you should expect to average 45 trans girls to win state T&F championships every year. This thread has turned up 2 examples. Seems like trans girls are pretty dramatically underrepresented.