Wheat is produced throughout the Midwest and is the principal cereal grain in the country. The U.S. is ranked third in production volume of wheat, with almost 58 million tons produced in the 2012–2013 growing season, behind only China and India (the combined production of all European Union nations is larger than China) The U.S. ranks first in crop export volume; almost 50 percent of total wheat produced is exported. The U.S. Department of Agriculture defines eight official classes of wheat: durum wheat, hard red spring wheat, hard red winter wheat, soft red winter wheat, hard white wheat, soft white wheat, unclassed wheat, and mixed wheat. Winter wheat accounts for 70 to 80 percent of total production in the U.S., with the largest amounts produced in Kansas (10.8 million tons) and North Dakota (9.8 million tons). Of the total wheat produced in the country, 50 percent is exported, valued at US$9 billion.