> 10% of raccoons that expose people or pets have rabies

I don't understand the language of this quote. What does it mean for an animal to expose people?

It's an odd framing. Out of R_t total raccoons, R_e bite or scratch (potentially "expose") humans. R_e / 10 of those were carrying rabies. So it could be that raccoons almost never bite/scratch humans, such that the behavioral effects of rabies are a significant motivator. It also could be that raccoons bite/scratch humans all of the time, and a ton of those raccoons have rabies. The latter is scary, but the former is likely the truth.

I wonder if increased interactions between humans and raccoons will lead to a reduction in that 10% figure (more reasons to bite humans).

It's that it's not 10% of racoons have rabies, but 10% of the ones that expose people to a bite scratch etc. The reason the numbers aren't the same, significantly less than 10% of them have rabies, is mainly that rabies itself can make them more hostile etc., on top of if bitten by a racoon that is more symptomatic seeming you are much more likely to get it checked out.

you would think that 100% of racoons that expose people to rabies have rabies.

An “exposure” in this instance to rabies would be physical contact - a bite, scratch, or from its saliva on an open wound for instance.