Population Economic conditions 81 Statistics 76 History 62 Social conditions 60 Demography 44 Population forecasting 37 Birth control 36 Labor supply 34 Congresses 31 Food supply 30 Fertility, Human 28 Population policy 25 Economic aspects 23 Agriculture 20 Housing 20 Statistics, Vital 20 Economic development 17 Emigration and immigration 17 Natural resources 17 Urbanization 17 Migration, Internal 13 Cities and towns 12 Maps 12 Mathematical models 12 Bibliography 10 Industries 10 Public welfare 10 Social aspects 10 Census 9