The government's decision to diversify from a trade-based, oil-reliant economy to one that is service- and tourism-oriented made property more valuable, resulting in the property appreciation from 2004 to 2006. A longer-term assessment of Dubai's property market, however, showed depreciation; some properties lost as much as 64% of their value from 2001 to November 2008. The large-scale real estate development projects have led to the construction of some of the tallest skyscrapers and largest projects in the world such as the Emirates Towers, the Burj Khalifa, the Palm Islands and the most expensive hotel, the Burj Al Arab. Dubai's property market experienced a major downturn in 2008 and 2009 as a result of the slowing economic climate. By early 2009, the situation had worsened with the Great Recession taking a heavy toll on property values, construction and employment. This has had a major impact on property investors in the region, some of whom were unable to release funds from investments made in property developments. , Dubai's foreign debt was estimated at approximately $80 billion, although this is a tiny fraction of the sovereign debt worldwide.