There are more than 1 billion Muslims worldwide, fewer than one fifth of whom are Arab. Islam is the principal religion of much of Asia, including Indonesia (which has the world's largest Muslim population), Malaysia, Pakistan, Bangladesh, Afghanistan, Azerbaijan, Turkmenistan, Uzbekistan, Tajikistan, Kyrgyzstan, Kazakhstan, Iran, Iraq, Syria, Jordan, the Arabian Peninsula states, and Turkey. India also has one of the world's largest Muslim populations, although Islam is not the principal religion there. In Africa, Islam is the principal religion in Egypt, Algeria, Tunisia, Djibouti, Gambia, Guinea, Libya, Mali, Mauritania, Morocco, Niger, Senegal, Somalia, and Sudan, with sizable populations also in Chad, Eritrea, Ethiopia, Ghana, Tanzania (where the island of Zanzibar is predominantly Muslim), and Nigeria.
In Europe, Albania is predominantly Muslim, and, historically, Bulgaria, Bosnia, Macedonia, and Georgia have had Muslim populations. Elsewhere in Europe, significant immigrant communities of Muslims from N Africa, Turkey, and Asia exist in France, Germany, Great Britain, and other nations. In the Americas the Islamic population has substantially increased in recent years, both from conversions and the immigration of adherents from other parts of the world. In the United States, the number of Muslims has been variably estimated at 2–6 million; 20% of the population of Suriname is Muslim.