Who are the Muslims?
One billion people from a vast range of races, nationalities and cultures across the globe - from the southern Philippines to Nigeria - are united by their common Islamic faith. About 18% live in the Arab world; the world's largest Muslim community is in Indonesia; substantial parts of Asia and most of Africa are Muslim, while significant minorities are to be found in the Soviet Union, China, North and South America, and Europe.
Taken from:http://www-scf.usc.edu/~uscmhsa/aboutislam.html