There currently are about 83.3 million dogs in the U.S. which are kept by around 56.7 million households, according to the American Pet Products Association (APPA). Dog bites are considered fairly common, but fatalities are not.
The most recent survey of dog bites conducted by the Centers for Disease Control and Prevention concluded that in 2001, 2002 and 2003 there were 4.5 million victims per year in the U.S.; that is 1.5 percent of the entire population. In 2016, there were 41 U.S. dog bite-related fatalities, which means 0.00000053 percent of dogs caused fatalities.
One of the scenarios that presents the highest risk of serious injury from a dog bite involves bringing a child into the home of a friend or relative who owns a high-risk dog, according to DogsBite.org, a public education website about dangerous dog breeds. The reverse scenario – a dog of one of these breeds temporarily staying at a child's home – is just as unsafe.
The following list, ranked in no particular order, is based on several studies covering various periods of time – one study relies on data from the U.S. and Canada between 1982 and 2014, another is based on research conducted in 2016 in the U.S., and a third study covers the years between 2005 and 2016.
All studies and resports agree: Pit bulls are the most dangerous dog breed. A review of 82 dog bite cases at a level 1 trauma center concludes that attacks by pit bulls are associated with higher morbidity rates and a higher risk of death than those by other breeds of dogs.