The U.S. has always had an interesting relationship with the science of evolution. As a foundational part of modern biology, the fact that species change over time is rarely debated in scientific circles (though exactly how change occurs is the subject of a lively, ongoing debate). The religious culture in the U.S., however, has traditionally seen evolution and other sciences as an enemy to certain religious beliefs. This stance has resulted in an American populace of which one-third completely reject the idea of evolution.

Pew Research today released a new survey looking at the beliefs of Americans with regards to evolution in 2013. The firm found that a full 33% of U.S. adults agree with the statement that “humans and other living things have existed in their present form since the beginning of time.” That leaves a slim majority of Americans (60%) agreeing that “humans and other living things have evolved over time.” Demonstrating just how religiously-colored Americans’ beliefs on evolution are, nearly half of those who accept evolution still believe that “a supreme being guided the evolution of living things for the purpose of creating humans and other life in the form it exists today.”

Though these overall numbers have not changed significantly in the past few years of Pew’s polling on the subject, it is now clear that members of the Republican party are rejecting evolution at an increasing rate. Pew’s poll found that 48% of Republicans polled this year reject evolution, while only 39% said the same thing back in 2009.

This represents one of the largest demographic shifts seen in Pew’s 2013 poll. Given that the overall numbers are similar from 2009 to 2013, this could mean that the Republican party is becoming less trustful of science, more religious, or both.

White mainline protestants, which make up a large portion of the Republican party’s base, are the most likely religious group in the U.S. to reject evolution (64%). Black protestants come next in the list with 33% rejecting evolution, and around 20% of those unaffiliated with any religion still believe humans exited in their present form since the beginning of time – more than even white mainline protestants (15%).

Democrats have shifted their views on evolution as well, though only slightly. 27% of Democrats now reject evolution, down 3% from the 30% who said the same in 2009. The Republican shift has widened the gap between the two main U.S. political parties’ acceptance of evolution, which widened from 10% in 2009 to 24% this year.