UH_IND_B1 is a 4-digit numeric variable.
Codes are found here.
Industry code of primary job last week - 1976-1982
These string values in the original data have been recoded as follows:
--- => -999 : Missing
- Those who have ever worked, have been in the labor force during the last 5 years, and are in rotation 4 or 8.
|1976 – 1982||X||X||-||X||X||X||X||X||X||X||X||X||X|