To the extent that developing countries remain the major suppliers, they have an incentive as well as an opportunity to exercise market leverage and gain economic advantage through cartel action and, in particular, through export taxation. The dependence of the developed market economy countries on the developing countries for supplies of primary products, including minerals, is highlighted by the fact that as a proportion of their apparent consumption, imports of primary products from developing countries were 20 per cent as against 3 per cent in the case of manufactures. Imports of fuel (coal, petroleum and gas) from the developing countries in 1979/80 constituted on average 51 per cent of apparent consumption in the developed countries (ranging from 77 per cent in Japan to 20 per cent in the US); those of other minerals averaged 25 per cent (ranging from 37 per cent in Japan to 14- per cent in the US).