If I am at home or at a friend's house, I will be on wifi. When out and about I will use public wifi if one is available. I will only use cellular connection if no free wifi is available.
Probably 60% wifi. Aside from at home I'll only use wifi if It's known to be faster then my cellular data connection. I have unlimited data so it's in my best interest to pick whichevers faster instead of always having to use it to not run my allotment out.