Thanks for the link! Be sure to read his books, too. You can get them from the library if you can't afford to buy them.
I read both of the books in depth, doing a shirt sleeve analysis of his tables & statistics, so I took a lot longer than necessary. I wouldn't recommend that most people do that, though. I recommend that you just read it & accept the numbers because they are irrefutable IMHO. "Trust me."
Very sophisticated statisticians have tried to tear apart his numbers & have finally resorted to the old canards of "It doesn't FEEEEEL right" or "My single little example from Nowheresville for one month show just the opposite." The beauty of his numbers is that he covers the whole US for a long period of time. Likewise, he is straight with the reader by showing outright where the broad assumptions, like "More Guns, Less Crime" fall down. Actually they are so few & far between that there is no need to hide those instances because the broad assumption DOES hold up.