Kevin Drum points out a recent Gallup Survey in which only 35% of Americans believe that evolution is "a scientific theory well-supported by evidence."

He then points to a 2001 study done by the National Science Foundation, in which 25% of Americans believe that the sun goes around the earth.

He says this is depressing, and he's probably right...but you know me, and I like to look on the sunny side of life. My intuition tells me that scientific literacy is most likely at an all-time high, and that while it's not great, it's probably a hell of a lot better than it was in decades and centuries past.

So I looked around the web a bit, trying to find historical comparisons. But scientific literacy actually hasn't been measured very long, or very regularly, until very recently. I found reference to a 1957 study by an association of science writers, but couldn't find any of the results.

Then I came across this, a comparison of American and European scientific literacy, using very similar questions and methodology, done in the 90's (It's the 6th reference, "The measurement of civic scientific literacy" by J.D. Miller).

If you think our scientific literacy is depressing, try this on for size:

United States
Literate: 12%
Partial: 25%
Not: 63%

European Union
Literate: 5%
Partial: 22%
Not: 73%

And also says:

In previous estimates of civic scientific literacy, Miller has used a threshold level of 67 or more, reflecting the ability of a respondent to get two-thirds of the possible points on the construct vocabulary index. When this standard is applied to the 1995 U.S. data, 27.2 percent of Americans score at or above the 67 point level, compared to 20.2 percent of Europeans. This result suggests that approximately three of four adults in Europe and the United States would be unable to read and understand news or other information that utilized basic scientific constructs such as DNA, molecule, or radiation.

This isn't to excuse American ignorance, but simply to point out that it isn't a uniquely American phenomenon. Scientific literacy is generally worse outside the US, and even moreso when you start looking an non-industrialized nations.

But you want to read something that's really depressing? Try the comments section of Drum's post.