What method was used to produce the bivariate (i.e., percentage by number) maps of county-level estimates?
For all indicators, the data distribution for the number of adults and the percentage of adults was based on three classes or categories of natural breaks. The gradation of the percentage of adults by the total number of adults was mapped using small to large symbols of three different colors for a total of nine levels. See related information on interpreting symbols and colors in the maps. For the definition of natural breaks, see the glossary.