If all of this is self reported and free form (write in categories), this could just be more of an exercise in language then in actual profession.
Also does this include part time work or those with jobs who are also students?
https://cps.ipums.org/cps/
Which is a project to, among other things, "Harmonize [Current Population Survey] data to be compatible over time".
The Current Population Survey is run by professional statisticians and well documented:
http://www.census.gov/cps/methodology/ioclassification.html
The classifications have some amount of subjectivity, but they probably aren't wildly arbitrary.
If all of this is self reported and free form (write in categories), this could just be more of an exercise in language then in actual profession.
Also does this include part time work or those with jobs who are also students?