However, due to an influx of immigrants and guest workers from non-Muslim countries, such as India, the Philippines and Sri Lanka, the overall percentage of Muslims in the country has declined since the late 20th century. According to the CIA's World Factbook, the country's 2001 census indicate that 81.2% of Bahrain's population was Muslim (Shi'a and Sunni), 5% were Christian, and 14% practiced other Asian or Middle Eastern religions like Hinduism.
The Al Khalifa ruling family and its supporting tribes adhere to the Maliki school of Islamic jurisprudence, while the Huwala Sunnis follow the Shafi'i school. There is also a large population of the South Asian Sunni Muslim residents who follow the Hanafi school.following the Jafari school.
The country observes the Muslim feasts of Eid al-Adha, Eid al-Fitr, the Prophet Muhammad's birthday (Mawlid), and the Islamic New Year as national holidays.
Political liberalisation under King Hamad has seen Islamist parties contest Bahrain's elections and become a dominant force in parliament. Sunni Islamist parties, the salafist Asalah and the Muslim Brotherhood affiliated Al-Menbar Islamic Society are two of the largest parties in parliament, while the Shia Islamist Al Wefaq was expected to become the dominating party after 2006's general election having boycotted the 2002 poll. In the 2006 election Wefaq received the backing of the Islamic Scholars Council which helped it seventeen of the eighteen seats it contested. In the 2010 election, they increased their representation by one seat, winning all the constituencies they contested, to take 18 of the 40 available parliamentary seats.
The Bahrain Grand Mosque in Manama is the country's biggest mosque.