Merritt Clifton, the editor of a US magazine "Animal People",...

Merritt Clifton, the editor of a US magazine "Animal People", tabulated all the reported incidents of dog attacks in the US and Canada over the period 1982-2006 and found that pit bulls, Rottweilers, Presa Canarios and their mixes are responsible for 74% of attacks that were included in the study, 68% of the attacks upon children, 82% of the attacks upon adults, 65% of the deaths, and 68% of the maimings.

http://www.dogbitelaw.com/Dog%20Attacks%201982%20to%202006%20Clifton.pdf

Cheers
SBC