The measurement was whether one thought the following statement was true or false: "Human beings, as we know them, developed from earlier species of animals." Answers were multiple choice: true, false, not sure or does not know.
The full ranking:
(Via stranger fruit, where commenters have noted a possible correlation with rankings of levels of happiness. It doesn't look like much of a correlation--the happiness rankings were 1. Denmark, 2. Switzerland, 3. Austria, 4. Iceland, 5. Bahamas, 23. United States, 35. Germany, 41. Britain, 62. France, 82. China, 90. Japan, 125. India. There's a slightly better correlation with rankings of percentage of atheists: 1. Sweden, 3. Denmark, 4. Norway, 6. Czech Republic, 7. Finland, 8. France, 10. Estonia, 11. Germany, 13. Hungary, 14. Netherlands, 15. Britain, 16. Belgium, 17. Bulgaria, 18. Slovenia, 21. Latvia, 22. Slovakia, 23. Switzerland, 24. Austria, 27. Spain, 28. Iceland, 32. Greece, 34. Italy, 37. Lithuania, 42. Portugal, 43. United States. Turkey and Cyprus didn't make the top 50 for percentage of atheists.)
UPDATE (February 20, 2009): It is interesting that western democracies without a strong history of church and state are those where religion is weakest and acceptance of evolution is highest. Turkey, the only OECD country with lower acceptance of evolution than the United States, is a Muslim democracy with a strongly enforced separation of church and state. Iceland and Denmark, the top two, are Lutheran, and Sweden, at #3, was officially Lutheran until it began introducing the separation of church and state in 1995. France and Japan, at #4 and #5, are perhaps counter-examples, both rounding out the bottom of the top five and having fairly strong separation of church and state, though Japan's was first imposed by the U.S. occupation after WWII. The UK, at #6, is Anglican; Norway, at #7, is Lutheran but expected to remove the official religion clause from its Constitution by 2012; Belgium, at #8, is officially Catholic and also funds other religions; Spain, at #9, is officially Catholic; Germany, at #10, guarantees freedom of religion but the state funds both Catholic and Protestant churches via "church tax"; Italy, at #11, is Catholic; the Netherlands, at #12, has constitutional freedom of religion but funds religions.