Urban growth and population densities.
D001334:Automobile Driving; D004463:Ecology; D049673:History, 20th Century; D006798:Housing; D006801:Humans; D009820:Ohio; D011156:Population Density; D011158:Population Growth; D013223:Statistics as Topic; D013997:Time Factors; D014481:United States; D014507:Urbanization / Q000266:history*