Citing a 2008 study, the U.S. Center for Disease Control estimated in 2015 that 4.5 million people in the USA are bitten by dogs each year. A 2015 study estimated that 1.8% of the U.S. population is bitten each year. In the 1980s and 1990s the US averaged 17 fatalities per year, while since 2007 this has increased to an average of 31. 77% of dog bites are from the pet of family or friends, and 50% of attacks occur on the property of the dog's legal owner.
The dogs' value to early human hunter-gatherers led to them quickly becoming ubiquitous across world cultures. Dogs perform many roles for people, such as hunting, herding, pulling loads, protection, assisting police and military, companionship, and, more recently, aiding handicapped individuals. This influence on human society has given them the nickname "man's best friend" in the Western world. In some cultures, however, dogs are also a source of meat.