The overwhelming majority of the economic base in the San Joaquin River watershed is provided by agriculture. The valley is widely considered one of the most productive farming regions in the world, and the top four U.S. counties ranked by agricultural production are all located in the San Joaquin watershed and Tulare Basin. The crops grown in these four counties alone are valued at over $12.6 billion annually, while the production of the entire valley is estimated at more than $14.4 billion. The main crop in the valley by annual sales is cotton, but more than 200 types of produce are grown along the San Joaquin River and in the Tulare Basin, including rice, almonds and lettuce. Livestock raising is also a major business in the valley. This prodigious output has earned the basin many names, including the "breadbasket" or "salad bowl" of the United States.