A great statistic in Waiting for Superman

A great statistic in Waiting for Superman: 1 in 57 doctors is removed for poor performance; 1 in 97 lawyers is; and (drumroll please), one in 2,500 teachers is!  This reminds me of the classic interview in The Cartel with the head of the NJ teachers union: when confronted with the fact that only 0.03% of teachers are dismissed for poor performance, she says (from memory): "Isn't it wonderful that 99.97% of teachers are doing a great job.  Wouldn't it be great if such a high percentage of doctors were so effective?"  (Again, I am NOT making this up!)