This map of U.S. states and territories depicts dog attacks on U.S. Postal Service workers per 100,000 households. The highest attack rates were in Iowa (7.3 attacks per 100,000), Missouri (7.2) and Ohio (6.6). The areas with the lowest rates of dog attacks were Puerto Rico (1.6 attacks per 100,000 households), South Dakota (1.7) and Guam (1.9). Broadly, attack rates are higher in the Midwest.