A quick explanation of the table - the percentage score is the number of total national team players divided by the total number of youth players in that state in 2010 (the only year for which there is data). This percentage reflects the efficiency or regularity with which a given state contributes players of the highest caliber.
Arizona and Missouri make the list for contributing one player because they have comparatively few youth players whereas California contributes 7 players but has a very large youth soccer league.
Why do some of these states do so much better in training their youth for prime time? Does Illinois have better structures in place for helping to identify talented youth - as they are more than twice as effective than the next state.
Can these be duplicated across other states?