Razib pulls some data from the General Social Survey and find that not only are Catholics more likely to consider the theory of evolution to be correct than Protestants, conservative Catholics are more likely to consider it correct than liberal Protestants. 58% of Catholics who also identify as politically conservative (and 71% of those who identify as politically liberal) agreed with the statement, "Humans beings developed from animals". However, only 26% of Protestants who identify as politically conservative and 53% of those who identify as politically liberal agreed with that statement.
It turns out, however, that race is a significant factor in the results. Many Protestants who are Black are politically liberal by reject evolution. If you filter the results on non-Hispanic whites, 65% of politically liberal Protestants consider evolution to be correct.
I'm a little surprised that so many Catholics actually doubt evolution, given that the Catholic Church has never been explicitly against the theory of evolution and Pope Pius XII specifically stated there was no conflict between the faith and evolution back in his encyclical Humani Generis back in 1950, something John Paul II echoed in his letter Truth Cannot Contradict Truth in 1996. However, since concern about evolution is fairly common among religious people in the US overall, it's probably not hugely surprising.