The USA TODAY Diversity Index was created in 1991 to measure how racial and ethnically diverse a population is. It uses the percentage of each race county by the federal government -- white, black, Asian, American Indian, Native Hawaiian -- and each ethnicity -- Hispanic of non-Hispanic -- to calculate the change that any two people are from different groups. The result ranges from 0 (no diversity) to 100. The 2009 nation index was 52. That means that the chance of two people being different is slightly more than half. In 1980, the index was 34.