In 1783, the al-Khalifa family captured Bahrain from the Persians. In order to secure these holdings, it entered into a series of treaties with the UK during the 19th century that made Bahrain a British protectorate. The archipelago attained its independence in 1971. Facing declining oil reserves, Bahrain has turned to petroleum processing and refining and has transformed itself into an international banking center. In January 2006, the United Nations Economic and Social Commission for Western Asia found that in a region experiencing an oil boom, Bahrain has the fastest growing economy in the Arab world. According to the 2006 Index of Economic Freedom published by the Heritage Foundation/Wall Street Journal, Bahrain also has the freest economy in the Middle East and is 25th freest overall in the world. In 2008, Bahrain was named the world’s fastest growing financial centre by the City of London’s Global Financial Centres Index. Continued strong growth hinges on Bahrain's ability to acquire new natural gas supplies as feedstock to support its expanding petrochemical and aluminum industries. However, unemployment, especially among the young, and the depletion of oil and underground water resources are long-term economic problems.