Starting from the mid-1980s, Cuba experienced a crisis referred to as the "Special Period". When the Soviet Union, the country's primary source of trade, was dissolved in late 1991, a major supporter of Cuba's economy was lost, leaving it essentially paralyzed because of the economy's narrow basis, focused on just a few products with just a few buyers. National oil supplies, which were mostly imported, were severely reduced. Over 80% of Cuba's trade was lost and living conditions declined. A "Special Period in Peacetime" was declared, which included cutbacks on transport and electricity and even food rationing. In response, the United States tightened up its trade embargo, hoping it would lead to Castro's downfall. But the government tapped into a pre-revolutionary source of income and opened the country to tourism, entering into several joint ventures with foreign companies for hotel, agricultural and industrial projects. As a result, the use of U.S. dollars was legalized in 1994, with special stores being opened which only sold in dollars. There were two separate economies, dollar-economy and the peso-economy, creating a social split in the island because those in the dollar-economy made much more money (as in the tourist-industry). However, in October 2004, the Cuban government announced an end to this policy: from November U.S. dollars would no longer be legal tender in Cuba, but would instead be exchanged for convertible pesos (since April 2005 at the exchange rate of $1.08) with a 10% tax payable to the state on the exchange of U.S. dollars cash though not on other forms of exchange.