Following Ottoman rule, Qatar became a British protectorate in the early 20th century until gaining independence in 1971. Qatar has been ruled by the House of Thani since the early 19th century. Sheikh Jassim bin Mohammed Al Thani was the founder of the State of Qatar. Qatar is a hereditary monarchy and its head of state is Emir Sheikh Tamim bin Hamad Al Thani. Whether it should be called a constitutional or an absolute monarchy is a matter of opinion. In 2003, the constitution was overwhelmingly approved in a referendum, with almost 98% in favour. As of early 2017, Qatar's total population was around 2.6 million: 313,000 Qatari citizens and 2.3 million expatriates.