I am attempting to extract variables from 1870-2010, however the 1870-1900 samples are missing. Codebook attached
It appears as though this is a result of the case selection on the EMPSTATD variable in your extract. EMPSTATD is not an available variable in 1870-1900, so the case selection effectively filters out all cases from those samples. You can obtain data from those samples by revising your extract and by removing the case selection on the EMPSTATD variable.