The United Arab Emirates (UAE) is a federation of seven states formed in 1971 by the then Trucial States after independence from Britain. Although each state maintains a large degree of independence, the UAE is governed by a Supreme Council of Rulers made up of the seven emirs, who appoint the prime minister and the cabinet. The relative political and financial influence of each emirate is reflected in the allocation of positions in the federal government. The ruler of Abu Dhabi whose emirate is the UAE's major oil producer is president of the UAE. The ruler of Dubai, which is the UAE's commercial center, is vice president and prime minister. The UAE is one of the most liberal countries in the Gulf, with other cultures and beliefs generally tolerated. However, politically it remains authoritarian. It was the only country in the region not to have elected bodies until December 2006, when it convened a half-elected federal assembly which was restricted to a consultative role. The UAE holds about 10 percent of the world’s proven oil reserves and the world’s fifth-largest natural gas reserves. Since Abu Dhabi first started exporting oil in 1962, the UAE has undergone a profound transformation from an impoverished region of small desert principalities to a modern state with a high standard of living. The country has grown from a quiet backwater to one of the Middle East's most important economic centers. To reduce its dependence on oil and natural gas revenues, the UAE has undertaken efforts in recent years to diversify its economy by investing in tourism, aluminum production, re-export commerce, and telecommunications. The UAE's per capita GDP is on par with those of leading West European nations.