Islam may be most closely associated with the Middle East, where it emerged in Arabia in the seventh century, but today the region is home to only one in five of the world's Muslims, according to a study of the religion's global distribution. The world's Muslim population stands at 1.57 billion, meaning that nearly one in four people practise Islam, according to the US Pew Forum on Religion and Public Life, which published the survey. This compares to 2.25 billion Christians. The top five Muslim countries in the world include only one in the Middle East ‑ Egypt ‑ behind Indonesia, Pakistan, India and Bangladesh, in that order. Russia, the survey shows, has more Muslims than the populations of Libya and Jordan combined. Germany has more Muslims than Lebanon. China has a bigger Muslim population than Syria. The work, the largest of its kind, was the result of three years of research examining data from 232 countries and territories.
The portrait it provides of Islam's distribution could have a profound influence on public policy in the west, and on attempts by the US, British and other governments to reach out to Muslims. Extrapolating the figures from the survey, the Islam that is largely practised around the world, particularly in large swaths of Asia, is more moderate and integrated than its stereotypical characterisation as an often militant and intolerant faith. The reality, as described by Mapping the Global Muslim Population, is that two out of three Muslims are Asians, while the 38 million Muslims in Europe, if treated as a separate group, would be the ninth largest in the world, behind Turkey, with a population of 71 million, and ahead of Algeria, with 34 million.
Significantly, one in five of Muslims now lives in a country where they are represented as a religious minority, with three-quarters of that number concentrated in five countries: India (161 million), Ethiopia (28 million), China (22 million), Russia (16 million) and Tanzania (13 million). The survey also attempted to quantify the relative sizes of the two main branches of Islam - Sunni and Shia - but came up against the difficulty that many national demographers did not distinguish between the two. It ended up suggesting that Shias, concentrated largely in four countries including Iran and Pakistan, probably made up between 10 and 13% of Muslims.
http://www.guardian.co.uk/world/2009/oct/08/muslim-population-islam-survey