Mongabay.com has provided graphs of food prices for the period 2000-2009.
In general wheat, rice , maize and soybean prices increased over the decade but increased markedly to a peak by 2.5-4.0 times the start 2000 value (in parallel with oil prices) just prior to the Global Financial Crisis but then dropped (together with pil prices) to about 1.6-2.4 times the start 2000 value.
In the case of soybeans, the price then soared in 2009 to $902/t, or 444% of (4.4 times) the start 2000 value.
The 2000-2009 key food prices are summarized below.
Wheat, US (Hard Red Wheat) price in US dollars per metric tonne ($/t) rose from 122 (100%; start 2000) to a peak of 431 (353%; prior to the financial crash) and then fell to 214 (175%; end 2009).
(For graph see: Wheat, US (Hard Red Wheat) price chart, 2000-2009, Mongabay (2010): http://www.mongabay.com/images/commodities/charts/wheat.html ).
Maize (corn) price in US dollars per metric tonne ($/t) rose from 107 (100%; start 2000) to a peak of 277 (259%; prior to the crash) and then fell to 176 (164%; end 2009).
(For graph see Maize (corn) price chart, 2000-2009, Mongabay (2010): http://www.mongabay.com/images/commodities/charts/maize.html ).
Soybeans price in US dollars per metric tonne ($/t) rose from 203 (100%; start 2000) to a peak of 580 (286%; prior to the financial crash), then fell to 335 (165%; mid 2009) but then increased to 902 (444%; end 2009)..
(For graph see Soybeans price chart, 2000-2009, Mongabay (2010): http://www.mongabay.com/images/commodities/charts/soybean.html ).
Rice, Thailand, 5% price in US dollars per metric tonne ($/t) rose from 220 (100%; start 2000) to a peak of 868 (404%) prior to the financial crash) and then fell to 517(235%; end 2009).
(For graph see Rice, Thailand, 5% price chart, 2000-2009, Mongabay (2010): http://www.mongabay.com/images/commodities/charts/rice.html ).