Estonia's constitution guarantees freedom of religion, separation of church and state, and individual rights to privacy of belief and religion. According to the Dentsu Communication Institute Inc, Estonia is one of the least religious countries in the world, with 75.7% of the population claiming to be irreligious. The Eurobarometer Poll 2005 found that only 16% of Estonians profess a belief in a god, the lowest belief of all countries studied (EU study). According to the Lutheran World Federation, the historic Lutheran denomination remains a large presence with 180,000 registered members.