Grain market analysts eagerly await each USDA quarterly report on grain and soybean stocks. Analysts can study industry trends and such consumption data as is available to help formulate estimates of past and future demand for corn, wheat, soybeans and other crops, as many do. However, USDA's estimates of each crop's stocks at the end of each quarter provide the only measure of how much of each actually disappeared. That is to say, how much was used in some fashion during the preceding three months and what volume is still available for future use.Analysts must modify their assumptions about demand from all of the various sectors, so that they fit with the volumes of total use during the quarter indicated by USDA numbers and with the volu...