Fewer U.S. Republicans believe in evolution now than five years ago, with a Pew Research poll finding an 11 percentage point drop.

In a poll of almost 2,000 Americans, 43 percent of Republican respondents said they believe humans have evolved over time, a drop from 54 percent in 2009, a Pew release said Monday.

Sixty-seven percent of Democratic respondents said they believe in evolution, a rise of 3 percent from 2009.

The overall statistic taken from the entire sampling group found 60 percent in the survey agreed with the statement "humans and other living things have evolved over time." Thirty-three percent said "humans and other living things have existed in their present form since the beginning of time."

Party differences remained even when factors such as the racial and ethnic composition, and religious and educational background of the political groups were taken into account, the Pew researchers said.

"It's an intriguing finding that is suggestive of greater polarization," Cary Funk of the Pew Research Center's Religion & Public Life Project and Social & Demographic Trends project told NBC News.

The survey was conducted by telephone between March 31 and April 8 with a representative sample of 1,983 U.S. adults age 18 or older. The margin of sampling error was plus or minus 3 percentage points.