75-100 is a pretty good crowd; don't know if there's that many here at USABDA's dances.

"Dancing is a contact sport; football is a hitting sport" - Vince Lombardi

I live in Vermont, and there aren't that many chances to go out Ballroom dancing here. Since moving here, though, I have attended (almost) every monthly dance that the local USABDA chapter has sponsored.
I'm not good at judging crowds, but I'd say these monthly dances attract at least 75-100 people. That seems pretty good for such a rural state, in my opinion.
I really enjoy these dances, and lots of people travel a fair distance to attend so I'll guess that they enjoy them as well!