Population History 76 Birth control 66 Economic conditions 59 Social conditions 57 Fertility, Human 42 Demography 31 más ... Economic aspects 30 Population policy 29 Food supply 24 Migration, Internal 20 Natural resources 17 African Americans 16 Economic development 15 Emigration and immigration 15 Human ecology 14 Population forecasting 13 Agriculture 12 Race relations 12 Pollution 11 Cities and towns 10 Economic history 10 Malthusianism 10 Ethnic relations 9 Ethnology 9 Families 9 Minorities 8 Politics and government 8 Ecology 7 Economic policy 7 menos ...