Those numbers are a real mystery, and nothing I've read here explains them, but I CAN enlighten all as to what the actual instructions from the census bureau instruct as to the completion of columns 30, 31, and 32 - which read thus:
SURVIVORS OF THE CIVIL WAR.
192. Column 80. Whether a survivor of the Union or Confederate Army or Navy.—This question should be asked as to all males over 50 years of age who were born in the United States and all foreign born males who immigrated to this country before 1865. Write "UA" if a survivor of the Union Army; "UN" if a survivor of the Union Navy; "CA" if a survivor of the Confederate Army; and "CN" if a survivor of the Confederate Navy. For all other persons leave the column blank.
BLIND AND DEAF AND DUMB PEBSONS.
193 Column 31. Whether blind (both eyes). —If a person is either totally or partially blind, in both eyes, so as not to be able to read even with the help of glasses, write "Bl." For all other persons leave the column blank.
194. Column 82. Whether deaf and dumb. —If a person is both deaf and dumb, write "DD." For all other persons leave the column blank. Persons who are deaf but not dumb, or persons who are dumb but not deaf, are not to be reported.