Bears were once commonly observed along roadsides and within developed areas of Yellowstone National Park. Bears were attracted to these areas by the availability of human foods in the form of handouts and unsecured camp groceries and garbage. Although having bears readily visible along roadsides and within developed areas was very popular with park visitors, an average of 48 bear-caused human injuries occurred each year from 1930 through 1969. Rocky Mountain grizzly bears have killed several people in the park since the 1970s.