Back in May it was 22. That's when the card hit nearly $100,000 at auction and I cited the PSA pop report for 10s in another thread:
http://www.net54baseball.com/showthread.php?t=254951
I figured that a bunch of 9s would be resubmitted, plus other raw cards sent in, and the population of 10s would go up after the auction. Hasn't happened, yet, it seems (since May).