Koivisto's policy was maintained only briefly after Esko Aho was elected Prime Minister. In 1991, the markka was pegged to the currency basket ECU, but the peg had to be withdrawn after two months with a devaluation of 12%. In 1992, Finland was hit by a severe recession, the early 1990s depression in Finland. It was caused by several factors, the most severe being the incurring of debt, as the 1980s economic boom was based on debt. Also, the Soviet Union had collapsed, which brought an end to bilateral trade, and existing trade connections were severed. The most important source of export revenue, Western markets, were also depressed during the same time, in part due to the war in Kuwait. As a result, by some opinions years overdue, the artificial fixed exchange rate was abandoned and the markka was floated. Its value immediately decreased 13% and the inflated nominal prices converged towards German levels. In total, the value of the markka had decreased 40% as a result of the recession. Also, as a result, several entrepreneurs who had borrowed money denominated in foreign currency suddenly faced insurmountable debt.