Islam is the world's second largest religion after Christianity. According to a 2009 demographic study, Islam has 1.57 billion adherents, making up 23% of the world population.
Large communities of Muslims are found in China, the Balkans, and Russia. Approximately 50 countries are Muslim-majority. About 20% of Muslims live in Arab countries. Maldives and Saudi Arabia have the highest Muslim percentages with 100% of both the countries population as Muslims.
Religion and state is the role of religion in politics based on the constitutions: Islamic state indicates use of Sharia law as a form of legislation; state religion indicates that Islam as the official religion of a country, where Sharia courts may be used; secular indicates that government institutions are formally separated from religion; and none indicates that the state has neither adopted a state religion, declared an Islamic state, nor declared a secular state.
The Muslim countries are mainly monarchies and presidential republics.
