I don't know of any national numbers on the subject. I know that just recently the NY Times did a story on North Carolina permit holders who committed crimes. They used all crimes not just gun crimes in an attempt to portray CCW holders as a lawless and dangerous bunch. All this to counter HR 822. However, when their numbers were compared to the entire state population it was shown that CCW holders had half the rate of criminal acts as compared to the entire population showing they were in fact much more law abiding. In fact members of Mayors Against Illegal Guns have been shown to be 4 times as likely as a CCW holder to commit a crime.