Relative Three-Year Average Unemployment Rates in Appalachia, 2009–2011(County Rates as a Percentage of the U.S. Average)
A three-year average unemployment rate is a measure of long-term structural unemployment. It is calculated by dividing the three-year sum of persons unemployed by the three-year sum of the civilian labor force. The percent of the U.S. average is computed by dividing the county unemployment rate by the national average and multiplying by 100. The map uses critical breaks such as the national average to organize the data into groups of common values.