B'Elanna said in VOY s7 "Lineage"there 140 humans aboard. Seen as the average crew count is always around 150 that's not that great diversity.
I'd count one Talaxian, two (or three depending on the episode) Vulcans, three Bolians, three Bajorans, one half-Ktarian, and one Betazoid.
Plus a half-Klingon, an Ocampa, a Cardassian.
If you're going to count Data I think you have to count the Doctor.
It always seemed to me there were a greater number of alien races in VOY. Perhaps it seemed that way because there were a larger proportion of aliens i the main cast.
Anyway most of those aliens came from the Marquis, so aside from Tuvok and Vorik was VOY a human-only crew initially?