Assuming you are talking about the track star, it would be kind of hard for her to make this list of top athletes in the 21st century when she passed away in 1998 :)
Good quiz, but maybe warn that it is US-centered because a list dominated by basketball, baseball and "football" will have the international audience of JetPunk scratching their heads. These sports are followed mainly in the USA, not very much elsewhere, so it would be fair to mention it.