Standardized choropleth map

http://upload.wikimedia.org/wikipedia/commons/thumb/7/78/USA_states_population_density_map.PNG/800px-USA_states_population_density_map.PNG

This is a standardized, areally averaged choropleth map. Cartographers often areally average choropleth map data in terms of density (persons per sq mile) or percentages (all data relativized to a scale of 0-100).