Size of lastWeeksGatheredTotals

I'm not sure what a fair way to measure what takes up space in a save is, but in my skimming through the JSON exported by Dump Game State I noticed lastWeeksGatheredTotals is long. Very long. 17,222 lines long, in fact. For perspective, my 170 slaves take up 115,414 lines.

I know a longer line would take more data, but every property has to take up something, right?

In my file, for example, RECRUITER has non zero data for slaveAssignmentRecruiter, naturally. It also has data for slaveAssignmentHeadgirlsuite, slaveAssignmentArcade, etc. There will never ever be data recorded there.

I don't know much about the way data is structured. Is this actually wasted space in a save? If so, how much?