By 750 CE, Islam had expanded to China, India, along the Southern shore of the Mediterranean and into Spain. By 1550 they had reached Vienna. Wars resulted, expelling Muslims from Spain and Europe. Since their trading routes were mostly over land, they did not an develop extensive sea trade (as for example the English and Spaniards). As a result, the old world occupation of North America was left to Christians.
Believers are currently concentrated from the West coast of Africa to the Philippines. In Africa, in particular, they are increasing in numbers, largely at the expense of Christianity.
Many do not look upon Islam as a new religion. They feel that it is in reality the faith taught by the ancient Prophets, Abraham, David, Moses and Jesus (Peace be upon them). Mohammed's (pbuh) role as the last of the Prophets was to formalize and clarify the faith and to purify it by removing foreign ideas that had been added in error.
Estimates of the total number of Muslims in the world vary greatly:
0.700 billion or more, Barnes & Noble Encyclopedia 1993
0.817 billion, The Universal Almanac (1996)
0.951 billion, The Cambridge Factfinder (1993)
1.100 billion, The World Almanac (1997)
1.200 billion, CAIR (Council on American-Islamic relations)
At a level of 1.2 billion, they represent about 22% of the world's population. They are the second largest religion in the world; Christianity has 33%.
Islam is growing about 2.9% per year which is faster than the total world population which increases about 2.3% annually. It is thus attracting a progressively larger percentage of the world's population. The number of Muslims in North America is in dispute: estimates range from under 3 million to over 6 million. The main cause of the disagreement appears to be over how many Muslim immigrants have converted to Christianity since they arrived in the US. Statistics Canada reports that 253,260 Canadians identified themselves as Muslims (0.9% of the total population) during the 1991 census. Those figures are believed to be an under-estimate.