(CNN) - A substantial and growing chunk of the country believes that President Obama, a self-described Christian, is Muslim, while only about a third of Americans are able to correctly identify his religion, according to a survey released Thursday.
Nearly one in five Americans believe Obama is a Muslim, up from around one in 10 Americans who said he was Muslim last year, according to the survey, conducted by the Pew Forum on Religion and Public Life.
While most of those who think Obama is Muslim are Republicans, the number of independents who believe he is Muslim has expanded significantly, from 10 percent last year to 18 percent now.
The number of Americans who express uncertainly about the president's religion, meanwhile, is much larger and has also grown, including among Obama's political base. For instance, fewer than half of Democrats and African-Americans now say that Obama is Christian.