Nearly one in five people, or 18 percent, said they think Obama is Muslim, up from the 11 percent who said so in March 2009, according to a poll released Thursday. The proportion who correctly say he is a Christian is down to just 34 percent.
The largest share of people, 43 percent, said they don't know his religion, an increase from the 34 percent who said that in early 2009.
...
In a separate poll by Time magazine/ABT SRBI conducted Monday and Tuesday — after Obama's comments about the mosque — 24 percent said they think he is Muslim, 47 percent said they think he is Christian and 24 percent didn't know or didn't respond.