In 2012, there were 2113 reports of attacks from pit bull attacks and close pit mixes. Including 884 children, 726 adults, 215 deaths, and 1181 injuries. Pit Bulls accounted for 60% of 2012 dog related attacks.
With the addition of other dangerous breeds, such as rottweilers and wolf hybrids, these account for 77% of dog related attacks, and 68% of attacks were fatal.
There is not doubt that these dogs are bred to be killers (as well as not), and every day the United States allows these innocent puppies to be put in the hands of those with criminal intent.
Introducing a special licensing system for dangerous breed ownership, and dangerous breed breeding should theoretically reduce the amount of dog attacks in the US.