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By 1991 the level of foreign indebtedness has drastically altered the role that many developing . countries play in the world trading system. Imports had been severely cut back and there was evidence of a scramble to export additional products, such as timber(木材),at heavy cost to the environment. Debt had emerged as the biggest single obstacle to development, with about 50 developing countries carrying a severe debt burden, over half of them in Africa.
At the end of 1990, developing countries owed $1,280 billion to Western countries, international aid agencies, the IMF, and banks. Their yearly earnings from international trade were under $1,000 billion ； the overall debt of developing countries was therefore mdre than the value of their exports. To service that debt—to pay interest and repay part of the capital—cost developing countries §143 .5 billion in 1990. They received $85 billion in aid and investment from abroad, thus paying richer countries nearly $60 billion more than they received. New aids and investment was wiped out by past debt. In 1991, according to OCED figures, the severely indebted low-income countries paid a higher proportion of their export revenue on debt service than at any time during the 1980s—31 .3% of such revenues, compared with 23. 8% in the 1980s.
Heavy debt burden has greatly blocked economy growth of the developing countries.