JamesSD makes a very valid distinction. I don't know if this is still true, but I read a few years ago that:
(a) most Arabs in the U.S. are Christian, not Muslim
(This is largely because historically the oppressed Christians of Lebanon, Syria, Iraq, etc. chose to emigrate to havens of religious liberty like the U.S. in much greater numbers than the Muslims of those countries)
(b) most Muslims in the U.S. are black, not Caucasian
(This is because most converts to Islam in the U.S. are black people in inner cities or prisons, though this is often the cartoonish perversion called the Nation of Islam.)
I suspect that both of these demographic observations are becoming less true nowadays as we foolishly allow hundreds of thousands of Muslims into the U.S. We should learn from Europe's fatal error in this regard.