151 Politics and government 132 Birth control 129 Congresses 109 Constitutional law 91 Constitutional history 78 Constitutional conventions 73 Constitutions 60 Rural development 53 Agriculture 53 Study and teaching 52 Economic conditions 50 Women 47 Education 42 Islam 35 History 33 Economic policy 31 Population 30 In-service training 30 Religion 30 Social conditions 30 Women in rural development 28 Relations 26 Research 25 Law 23 Industries 23 Social workers 22 Public welfare 21 Economic aspects 21 Regional planning 19 Geology