Gallup polls over the past 25 years have shown that that percentage of Americans that believe that “God created man in present form” has stayed constant at about 45%.

However, the percentage of people that believe that “the idea that God created human beings pretty much in their present form at one time within the last 10,000 years” is probably or definitely true is about 65% (as of 2007).

If we take this as a measure of the spread of basic science literacy it seems clear that this has remained stagnant over the last 25 years.

A related interesting fact is that roughly 50% of Americans have tried to convert someone to Christianity ( Gallup Poll ).