HD - Industries, Land Use, Labor 734,572
HC - Economic History and Conditions 378,718
HV - Social Pathology, Criminology 305,895
HQ - Family, Marriage, Women 261,777
HF - Commerce 243,374
HB - Economic Theory and Demography 223,878
HG - Finance 201,576
HN - Social History and Conditions 123,586
HE - Transportation and Communications 111,141
HT - Communities, Classes, Races 108,356
HM - Sociology 106,391
HX - Socialism, Communism, Anarchism 83,252
HJ - Public Finance 79,940
HA - Statistics 57,027
H - Social Science 42,041
HS - Societies 15,385
F - General American History 3
B - Philosophy 2
E - United States History 2
N - Visual Arts 2
NC - Drawing, Design, Illustration 1
PS - American Literature 1