The macroeconomic policies of the 1970s left Mexico's economy highly vulnerable to external conditions. These turned sharply against Mexico in the early 1980s, and caused the worst recession since the 1930s, with the period known in Mexico as La Década Perdida, "the lost decade", i.e., of economic growth. By mid-1981, Mexico was beset by falling oil prices, higher world interest rates, rising inflation, a chronically overvalued peso, and a deteriorating balance of payments that spurred massive capital flight. This disequilibrium, along with the virtual disappearance of Mexico's international reserves—by the end of 1982 they were insufficient to cover three weeks' imports—forced the government to devalue the peso three times during 1982. The devaluation further fueled inflation and prevented short-term recovery. The devaluations depressed real wages and increased the private sector's burden in servicing its dollar-denominated debt. Interest payments on long-term debt alone were equal to 28 percent of export revenue. Cut off from additional credit, the government declared an involuntary moratorium on debt payments in August 1982, and the following month it announced the nationalization of Mexico's private banking system.