Considering the sickening way they talk about their "fur babies"...
Considering how they cheer whenever a human is attacked and killed by a wild animal...
Considering the vicious way they speak about normal people who enjoy hunting...
I'd say marriage between a democrat and an animal would be a small step for them, and in a lot of cases would be a union of equals.
So I'm pretty sure the percentage of DUmp democrats that favor marriage with animals would be between the mid-thirties and upper forties.
A few other considerations:
1. How many of them are members of rabid animal- rights groups like PETA which view all animals as equal to if not superior to humans. After all, as PETA's clinically insane founder Ingrid Newkirk famously said, "A rat is a pig is a dog is a boy."
2. How many of them clearly buy into the mentality of "Love is love, it's discriminatory and bigoted to support one form of love and outlaw another."
3. How many of them are "Furries."
4. How many of them have no luck romantically with fellow humans.
I'd say mid- to upper- forties.