One, with his strategic question-asking abilities.
How may of them does it take to change a lightbulb? Can they help you change a tyre? What are they like giving a girl a good massage?
The cylons are unsure of where the Earth (Gaea) is, so perhaps as long as we can remain lost in space we're safe as the last outpost of humankind!
just you.. *scrambles vipers*
Not enough obviously!