The research by the Pew Forum on Religion and Public Life was three years in the making, covers 232 countries and provides a precise number for a population that has been estimated to range anywhere from 1 billion to 1.8 billion.

Islam is the world’s second-largest religion behind Christianity, which has an estimated 2.1 billion to 2.2 billion adherents. The report estimates that Shi’ites represent between 10% and 13% of the Muslim population, of which about 80% live in four countries: Iran, Pakistan, India and Iraq.

The report provides further evidence that while the heart of Islam might beat in the Middle East, its greatest numbers lie in Asia, home to more than 60% of the world’s Muslims.

Other findings:

• About 317 million Muslims – or one-fifth of the world’s Muslim population – live in countries where Islam is not the majority religion. The Muslim minorities are concentrated in fi ve countries: India (161 million), Ethiopia (28 million), China (22 million), Russia (16 million) and Tanzania (13 million).

• Two-thirds of all Muslims live in 10 countries. Six are in Asia (Indonesia, Pakistan, India, Bangladesh, Iran, and Turkey), three are in north Africa (Egypt, Algeria, and Morocco) and one is in sub-Saharan Africa (Nigeria).

• Indonesia has the world’s largest Muslim population, 203 million, or 13% of the world’s total.

• Europe is home to about 38 million Muslims, or 5% of its population. Germany appears to have more than 4 million Muslims – almost as many as North and South America combined.

• Of about 4.6 million Muslims in the Americas, more than half live in the United States, although they only make up 0.8% of the U.S. population.