David3, I have been digging more into the issue of area under grain crops for feed specifically and it is not an easy one to answer. Grains are first and foremost grown for human consumption. But yes, a lot goes to animal feed, especially corn. However, there are varied factors, many of which are economic - current prices, current growing conditions, yield quality and quantity. It seems hard to come to a firm conclusion as I have seen numbers from about 40% of all cereal grains globally to as much as 70%. I think 30% is still a fair factor but this should also be applied to the area under wheat as well as quite a lot of wheat goes to feed (eg about 70% of domestic use here in Australia). Still, that remains a really rubbery guess. I will recalculate with this adjustment and see what I get.