Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.
CLASSWK refers to the status of an economically active person with respect to his or her employment -- that is, the type of explicit or implicit contract of employment with other persons or organizations that the person has in his/her job. In general, the variable indicates whether a person was self-employed, or worked for someone else, either for pay or as an unpaid family worker. CLASSWK is related to EMPSTAT, which is used to define the universe in many samples.
Class of worker is often referred to as "status in employment" in other sources.