According to this:

https://film.jmcnetwork.com/film-crew-jobs-responsibilities/production-department/location-manager/unit-manager/

and other articles I've read, a unit manager actually belongs in the Location department, not in the Production Managers department, as instructed in the IMDb guide.

Current breakdown is as follows:

Location Management - 4,248

Production Management - 96,609

Additional Crew - 3,700

I'd be interested in IMDb's take on this and whether the UM's encountered in the Location section should still be transferred to the Production Manager section, or maybe the reverse.