The amount of food grown in Africa has only just recovered to the 1960 level of production today
"Production data per capita (of the total population) indicate that the amount of food grown on the continent per person rose slowly in the 1960s, then fell from the mid-1970s and has only just recovered to the 1960 level today."
Jules Pretty, Camilla Toulmin and Stella Williams, "Sustainable intensification in African agriculture, International Journal of Agricultural Sustainability 9 (1) 2011. 5. http://www.tandfonline.com/doi/abs/10.3763/ijas.2010.0583#.U0_dQVypNg0