volume Jeclined from 68.3 per cent in 1970 to 61.1 per cent in 1980. The reduced share of wheat 11.:as due tc the rapidly ir>creas­ inq volume of imports of maize, which rose at a ccrnpcurxi averaqe an!"'ual rate ··f 20.7 per cent betweef'. 1970 and 1980, increasir.q rna ize 's share in the tctal vel ume of cereal imports from 9. 2 per cent in 1970 to 20 per cent in 1980. Over the same perioo, the share of rice imports r..arqir.o1lly declined frcm 16.6 per cent to 16 . 3 pe r ce nt . 27. In rna ny parts of develcpinq Africa, the production of cer­ tain cereals is hampered by ecoloqical factors. Fer instance, except in p<•rts cf :tJorth Africa, the East African hiahlands, Ethiopia arrl the Sudar., wheat can be qrcwn or:ly at prohibitive cost. Conse·:uently, .P.frica is by far the least self-sufficient reqion in whe. t, producinq only abcut 11 per cer,t of tl'e wheat it cor.sur.1es. R ce can be orcwn in a wider ranqe of cour.tries, but nevertheless requires larae irriqation scherr.es to supplernen~. rain-fed cul ti. va tion. 28. The dat2 in table IV.A. 7 are even more reveal ira. Assuminq 200 kiloqram. of cereals to be a minimum cal erie i r.take per capita yearly it l!as beer fcurrl that practically all .t:he ccu ntries in the Ncrth Africa r, subreoicf' import a considerahle amount of th. s miPilr.um. What is more, in the case of the Libya!! Arab Jamahir ya the imports substa r.tially exceed the r:~inimum requirement. In Chac; a I!d Rwa rda the share of imported cereals is negl iqible. These data should r:ot however be misccPstrued to mean that de· ·elopi r.q Africa r ccu r>tries ca nnct step up production 