Iowa is located in the Central United States and is usually included in the Midwest region. The area that makes up the state’s territory came under United States jurisdiction through the Louisiana Purchase in 1803. Iowa’s agricultural efficiency has led it to become the nation’s third most productive agricultural state, only behind Texas and California in terms of total output. Approximately 87% of the total land area is dedicated to farmland. Corn and soybeans are the two most important crops, although they are each used largely to feed livestock. The economic base for Iowa began to shift in the late 20th century from agriculture to manufacturing and services. Although Iowa produces ten percent of the U.S. food supply, the value of Iowa's manufactured products is twice that of its agriculture. Other major industries include machinery, electrical equipment, printing and publishing, and fabricated products.