Forty-nine percent of Republicans don’t believe in evolution, a new Public Policy Polling survey found Tuesday.

The poll by the Democratic-leaning firm found that 49 percent of Republicans said they do not believe in evolution while 37 percent said they do believe in evolution. Another 13 percent said they were not sure.

In a sign that the issue still carries weight with GOP primary voters, Wisconsin Gov. Scott Walker (R) recently refused to say whether he believed in evolution.

The poll was conducted among 316 Republican primary voters. The margin of error was plus or minus 5.5 percentage points.