text: ince x (which is an import-wei ghte 6 sum of e :>:change rates ex­ pressed as units of foreign currency per unit of domestic curren­ cy) by the ratio of a consumer price index in the home country to an import-weighted combination of consumer price inceYes in partner countries. This measure is used tc indicate the extent to which movements in relative price levels have been offset by exchange rate adjustments. 109 E/ECA/C't-1. 9/5 VI. THE EXTERNAL SECTOR A. Foreion trade 1. Africa enccuntered great difficulties in its foreign trade in 19£1-1982. Ler.1and for its crude oil, coffee, copper, cocoa and other prime ry r:roducts decreased, and their prices also droppeC conEiderc:bly. Imports grew in l9el and the trade deficit \Jas tlte worst ever 1 at about $ 15.3 bill ion. Prel iminat;y es­ timates made by the ECA secretariat show that the 1982 deficit will be about $1(.2 billion. 2. Africa was the continent most affected by the decline in world trade in 1981-1982. Hhile the exports of the developing world dec rea sed in value by 2 per cent in 1981 1 the figure for Africa was rr.ore than 20 per cent. The corresponding falls in 1982 were IJ. 8 per cent and more than 15 per cent. 3. The value of the world trade (in US dollar terms) fell in 1981 for tl1e first time since 1958 1 and it continued to decline rapidly in 1982. Only the countries around the Persian Gulf suf­ fered as seriously as Africa. Value a/ Exports Imports Volume Exports Imports Unit value ~I Exports Imports Table VI.A.l Merchandis,~ trade of developing Africa (Percentage change over preceding year) 1980 1981 36.4 -20.4 3 7.4 15.8 . -6.1 -21.5 11.5 21.5 45.3 1.4 23.2 -4.7 Terms of trade 17. 9 6.4 Purchasing power of exports 10.7 -16.4 1982 
analysis: The text discusses the economic difficulties faced by Africa in the early 1980s, including a decline in foreign trade, a widening trade deficit, and a decline in the value of exports. It also mentions the impact of this decline on the continent's terms of trade and the purchasing power of its exports. This suggests that the text is primarily focused on economic issues, particularly international trade and development.