I consider myself 100% straight because I've never had sex with a man and I'm not turned on by the idea. I've contemplated the idea before, even fleetingly wondered what it might be like, but wasn't turned on by it. I think that to have a split in your preference (however inexact that might be), I think you have to at least fantasize regularly about the less-preferred gender, if not act upon it. Obviously everyone has their own definition though.