Google says the definition of 'bi-curious' is as follows:
"(of a heterosexual person) interested in having a sexual experience with a person of the same sex."
Aside from the small logical leap to apply it to homosexual people, surely "interest" would involve a bit more commitment to the venture than an idle thought of say, "I wonder if I might be attracted to the other gender?", at which point surely they're not really lesbian but bisexual?
Asking such a question as the OP did seems as silly as asking "are most straight people bi-curious" or "are most gay males bi-curious", IMO.
IMHO for me to be bi-curious in my own opinion, I would have to have had some sort of sexually-charged interest/curiosity in a particular guy, which I haven't. I have however pondered on one or two occasions whether I might be attracted to guys, to which my conclusion has been "probably not" (the first question answering this one really).