F - General American History 11,540
D - General History 54
E - United States History 10
S - General Agriculture 9
LC - Social Aspects of Education 7
PZ - Fiction 7
CR - Heraldry 6
PS - American Literature 6
QE - Geology 5
PQ - French, Italian, Spanish, Portuguese Literature 2
PR - English Literature 2
C - General History 1
CC - Archaeology 1
DS - Asia 1
HC - Economic History and Conditions 1
ML - Literature on Music 1
PN - General Literature 1
QH - Natural History and Biology 1
TD - Environmental Technology 1
UC - Maintenance and Transportation 1