Americans' Creationist Views on Human Origins
livescience.com
livescience.com
They're a solid outfit with a great track record; these numbers are sadly accurate.
What about missing poll options? Surely there must be some young-Earth creationists out there who nonetheless believe the human race is over ten thousand years old. In fact, there's a whole term for this: http://en.wikipedia.org/wiki/Old_Earth_creationism
I am fond of pointing out (as it annoys many people) that not only is intelligent design not incompatible with evolution, but also that "intelligent design" is pretty much implied by the tenets of most monotheisms. If you have an omnipotent god who sets the initial conditions of the big bang, then he can hardly fail to know perfectly well that the initial particle trajectories he programs in will lead, inevitably, to the formation of Earth and intelligent life thereon. Assuming that said deity had a choice in initial conditions, the fact that he chose the initial conditions that he did must mean that he designed everything in the universe, since from an omnipotent being's point of view setting the initial conditions is perfectly equivalent to setting everything up from scratch at T=1.37e10 years. (The alternative is that you have a deity who can't predict the outcome of quantum events, but what kind of crappy omniscience is that?)
As for your 'never met one', that's probably an anecdote about selection bias. We does these surveys because asking, "Hey, does anybody know any young-earth creationists? Like how many?" does not provide reliable data.