Islam is the second-largest religion in the world after Christianity, with an estimated following of 1.6 billion people living on all inhabited continents. The highest number of Muslims is found in the Asia-Pacific region, followed by the Middle East and North Africa, Sub-Saharan Africa, Europe and the Americas. The Asia-Pacific region is home to 62 percent of the world's Muslims, according to a 2011 report from the Pew Forum on Religion and Public Life. Pew estimates that the world Muslim population will increase by 35 percent to more than 2.1 billion by 2030.

History

Within 200 years of its founding in the 7th century, Islam spread from its roots in Mecca, Saudi Arabia to Egypt, North Africa, Spain and Syria, and into Persia and India by the end of the 10th century. Islam soon after moved into Turkey and sub-Saharan Africa. While Muslims maintain that Islam has always existed, it wasn’t until 610 that the prophet Mohammed began reciting verse from the Muslim god, Allah, through the angel Jibreel – that would become Islam’s holy book, the Quran.

Asia-Pacific

Indonesia is home to the largest numbers of Muslims in the world, with 204 million followers. Pakistan has 178 million Muslims, while India has 177 million and Bangladesh has 148 million. Bangladesh has the highest percentage of its population as Muslim, at 90 percent, followed by Kyrgyzstan, at 88 percent, according to Pew research data. The Pew reports also lists 74 million Muslims each in Iran and Turkey, 26 million in Uzbekistan, 23 million in China and 17 million in Malaysia. Muslims live in fewer numbers in Australia, New Zealand and the Philippines, according to the report.

Middle East and North Africa

About nine out of 10 people in the Middle East and North Africa are Muslim, or more than 205 million people, according to the Pew Center. Egypt tops the region with 80 million Muslims, followed by Algeria with 34 million, Morocco with 32 million, Iraq with 31 million and Sudan with 30 million, according to Pew data. There are 25 million Muslims in Saudi Arabia, 24 million in Yemen and 20 million in Syria. The number of Muslims in Israel has been growing rapidly over the past two decades. Pew Center research projects that more than 75 percent of Israel will be Muslim by 2030.

Sub-Saharan Africa

Muslims in Sub-Saharan Africa make up about 29 percent of the population, with countries in West Africa having the highest concentration of Muslims at 50 percent, according to Pew research. The most Muslims live in Nigeria, at 75 million, followed by 28 million in Ethiopia, 15 million in Niger, 13 million in Tanzania, and 12 million each in Mali and Senegal, according to Pew. The population of Sierra Leone has the highest Muslim concentration, at 71 percent, followed by 48 percent in Nigeria.

Europe

Russia, which Pew researchers included in Europe’s data, is home to 16.3 million, or more than half of the 29 million Muslims in the region. There are 4.7 million Muslims in France, 4.1 million in Germany, 2.8 million in the United Kingdom, 1.5 million in Italy and 1 million is Spain. Fewer than 1 million follow Islam in Belgium, Austria and Switzerland. Muslims make up about 35 percent of Macedonia and 18.5 percent of the population of Montenegro, according to Pew data.

Americas

Roughly 3 million Muslims live in the 51 countries of North America and Central and South America, according to the Pew Foundation. Canada has the highest concentration of Muslims in the region, with 940,000 followers of Islam, or 2.8 percent of its population. Argentina's 1 million Muslims account for 2.56 percent of its population, and 0.8 percent of the United States population, or 2.5 million people, is Muslim, according to Pew.