What is a quintile?
A quintile is 1/5 of the distribution of all county rates. Rates are divided into 5 equal subgroups (quintiles), ranging from highest to lowest. Each quintile contains as near as possible 20% of the distribution. In practical application, some quintiles in our maps do not cover the same number of people because some counties have the same rate, and these tied rates may make it impossible to divide the distribution equally. The map legend shows the ranges of death rates that define each map category and the number of counties in each category.
