How much have the parties that professions voted for changed?

[TheReckoning]

For example, today, cops tend to vote Republican, while college professors tend to vote Democratic.

100 years ago, would also expect cops to be more Republican than the nation at large, while college professors would be more Democratic?

Im just picking these two professions randomly because the have a specific partisan lean today, not because I feel they are more important than any other profession in this context.