These figures showcase the positive correlation between commemorating African-Americans and the percentage of African-Americans in counties. States where there is a high African-American population, tend to have more commemorations for African-Americans as well, however, the counties tend to be highly segregated, with a correlation to the commemoration policy.
Tretter, E. M. (2011). The power of naming: The toponymic geographies of commemorated African Americans. The Professional Geographer, 63(1), 34-54.