TD - Environmental Technology 2,442
TN - Mining Engineering and Metallurgy 1,958
T - General Technology 1,833
TL - Motor Vehicles and Aeronautics 1,184
TK - Electrical and Nuclear Engineering 1,133
TX - Home Economics 1,121
QE - Geology 694
TA - General and Civil Engineering 522
TR - Photography 504
TT - Arts and Crafts 454
TJ - Mechanical Engineering and Machinery 403
TS - Manufactures 403
TH - Building Construction 390
TP - Chemical Technology 366
C - General History 277
TC - Hydraulic and Ocean Engineering 270
E - United States History 238
TF - Railroad Engineering and Operation 89
D - General History 84
HE - Transportation and Communications 51
F - General American History 22
HS - Societies 18
L - General Education 17
TE - Highway Engineering 14
TG - Bridge Engineering 12
J - General Legislature 8
PR - English Literature 8
GB - Physical Geography 7
HD - Industries, Land Use, Labor 5
G - General Geography 4
LC - Social Aspects of Education 4
QC - Physics 4
S - General Agriculture 3
CR - Heraldry 2
HC - Economic History and Conditions 2
HM - Sociology 2
NK - Decorative Arts 2
PZ - Fiction 2
QA - Mathematics 2
Z - Books and Writing 2
AE - Encyclopedias 1
BL - Religions, Mythology, Rationalism 1
GA - Mathematical Geography and Cartography 1
GE - Environmental Sciences 1
GF - Human Ecology and Anthropogeography 1
GV - Leisure and Recreation 1
HF - Commerce 1
JX - International Law 1
LB - Theory and Practice of Education 1
N - Visual Arts 1
NC - Drawing, Design, Illustration 1
ND - Painting 1
PN - General Literature 1
PS - American Literature 1
Q - General Science 1
QK - Botany 1
RA - Public Medicine 1
SB - Plant Culture 1
VA - Navies 1