Also, w/r/t Sam’s post on how few Americans believe in evolution, I’d suggest there’s no way to ask an un-loaded question about evolution. Gallup uses “theory of evolution”, which is the sort of phrasing that could prompt coming down against it for fence-sitters; this is the primary rhetorical tack of creationists. Whereas a question that emphasized the fact that it is accepted and foundational to modern biology would have a distorting effect in the opposite direction. These effects can be pretty significant.
Though obviously his main point still stands; I blame the schools.