HD - Industries, Land Use, Labor 1,945
HF - Commerce 1,607
HE - Transportation and Communications 736
HT - Communities, Classes, Races 408
HB - Economic Theory and Demography 390
HG - Finance 344
HC - Economic History and Conditions 298
HM - Sociology 119
HV - Social Pathology, Criminology 109
HA - Statistics 93
HJ - Public Finance 49
H - Social Science 40
HN - Social History and Conditions 10
HQ - Family, Marriage, Women 7
HX - Socialism, Communism, Anarchism 1