In the 3-year period from 2006 to 2008, pit bull type dogs killed 52 Americans and accounted for 59% of all fatal attacks. Combined, pit bulls and rottweilers accounted for 73% of these deaths.

Pit Bull Statistics from to 2006-2008

Breeds of Dogs Involved in Fatal Human Attacks in the United States Between 1979 and 1998
A 2000 report issued by the Center for Disease and Control (CDC)1 reviewed a 20-year period to determine the types of dog breeds most responsible for U.S. dog bite fatalities.

Data for human dog bite-related fatalities (DBRF) identified previously for the period of 1979 through 1996 were combined with human DBRF newly identified for 1997 and 1998. Human DBRF were identified by searching news accounts and by use of The Humane Society of the United States' registry databank.
During 1997 and 1998, at least 27 people died of dog bite attacks (18 in 1997 and 9 in 1998). At least 25 breeds of dogs were involved in 238 human dog bite related fatalities during the past 20 years. Pit bulls and rottweilers were involved in over half of these fatalities and from 1997 to 1998 were involved in 67%.
During 1997 to 1998, fatal attacks were reported from 17 states; California 4; Georgia and North Carolina 3 each; Kansas, Texas, and Wisconsin 2 each; and Alaska, Arkansas, Colorado, Florida, Kentucky, Massachusetts, Michigan, Missouri, New York, South Dakota, and Tennessee 1 each.

Of 227 reports with relevant data, 55 (24%) human deaths involved unrestrained dogs off their owners' property, 133 (58%) involved unrestrained dogs on their owners' property, 38 (17%) involved restrained dogs on their owners' property, and 1 (< 1%) involved a restrained dog off its owner's property.

Four hundred and three dogs contributed to these attacks. In 160 deaths, only 1 dog was involved; in 49 deaths, 2 dogs were involved; and in 15 deaths, 3 dogs. Four and 7 dogs were involved in 3 deaths each; 5, 6, and 10 dogs were involved in 2 deaths each; and 11 and 14 dogs were responsible for 1 death each.

Breeds of Dogs Involved in Fatal Human Attacks in the United States Between 1979 and 1998, by Sacks, Sinclair, Gilchrist, Golab and Lockwood, Journal of the American Veterinary Medical Association, 2000

1All five authors of the CDC report strongly oppose breed-specific laws: Sacks, Sinclair, Gilchrist, Golab and Lockwood. Learn more: The CDC Fatal Dog Attack Report Issued in 2000 Was Positively Biased