SRDAYS is a 3-digit numeric variable with no implied decimals.
0: Not in universe
999: Unknown
For sample persons aged 18 and older who worked at a civilian job last year and who had any red, inflamed skin rashes in the past 12 months, SRDAYS reports the number of days that the person had skin rashes in the past 12 months.
This variable was included in the 1988 Occupational Health supplement.