Tableau partners with multiple sources for map data layers. The list of the sources are located here: About Tableau Maps | Tableau Software
For your question about occupations by zip code, that would be dependent upon the data source using those attributes. You might have to do bit of research on that question using one or more of the data sources. My personal thinking is that it would be the zip code of the employer (if they're cooperating) not the personal information of the employee's residence.
If this resolves your question, please mark this response as correct so others may find it useful in the future. Thx! Don