Plants constitute 93 percent of the world's diet. Cereals contribute two-thirds of all food, and among the cereals, wheat is the largest crop. The eight major cereals-namely wheat, maize, rice, barley, sorghum, oats, millet and rye-cover 56 percent of the world's arable land and are the major source of calories and protein for most of the world's people. Wheat, maize and rice account for 80 percent of global cereal production. Developing country wheat production during the decade of the 1970s increased at a rate of 4.8 percent per annum, the highest of all the cereals. Most of this production growth has occurred in the five major developing country producers-China, India, Argentina, Pakistan and Turkey-which collectively account for 82 percent of all developing country production. Among these major producers, China has registered the greatest production gains.