Large numbers of Iranians, too. And IIRC the Iranian community in the US (that is, the politically conscious and organized part) is made up mostly of pro-Shah fascistic assholes and their descendants, unlike that in Germany (reduplicate statement in brackets) which is mostly made up of people from the democratic/socialist wing of the revolution... who usually recognize that what Iran has had since Khomeini's death is not good but better than anything that has gone since Mossadegh's death...
Bottomline: I don't think they swung much in 2004.
A lot of Iranian-Americans that are in the pro-Shah camp don't consider themselves Muslim.