Over the long term, food prices have tended to decline in real terms, as the result of increased yields. Averaging over the four years 2011-14, the deflated price of grains and vegetable oils are respectively 15% and 14% lower respectively than those over the four years 1969-72; the prices of softs (cocoa, coffee, tea and sugar) are 35% lower. However, prices have tended to rise over the period since 2000. In 2011, grains prices were 92% higher than in 2000, vegetable oil prices 136% higher and softs prices 65% higher. Prices have dropped back slightly from 2012.
Gilbert C.L. 2015. "Food Prices, Food Price Volatility and the Financialization of Agricultural Futures Markets" Ferdi Policy Brief B144, December 2015.