Just 34% of Americans correctly say U.S. President Barack Obama is a Christian, while 44% say they don't know Obama's religion and 11% say he is a Muslim.
I'm not sure that this is entirely accurate - I believe the last time Obama was a member of a church was 2008, so it's quite reasonable for 44% of people to say that they don't know.
It's also quite possible (though not too probable) that Obama could have given up his Christian faith in the last 4 years.
Oh and not clear why Gallup doesn't consider Catholic to be Christian. Odd definition.