In FY 1991, high-value products exceeded traditional bulk products, something virtually unprecedented in U.S. agricultural exports...Canada and Mexico provided about 25 percent of the $20.8 billion of agricultural goods imported into the United States during October 1990-August 1991...U.S. agricultural exports generated $1.59 (an additional$62.8 billion) from each dollar received in 1990... .The cost of shipping grain overseas generally rose during the first half of 1991