The livestock population in 2001 included an estimated 97.2 million head of cattle, 59.1 million hogs, and seven million sheep and lambs. That year, there were 1.9 billion chickens, and 88 million turkeys. Milk production totaled 75 million metric tons in that year, with Wisconsin, California, and New York together accounting for much of the total. Wisconsin, Minnesota, and California account for more than half of all US butter production, which totaled 558,700 metric tons in 2001; in that year, the United States was the world's largest producer of cheese, with more than four million metric tons (24% of the world's total). The United States produced an estimated 16% of the world's meat supply in 2001. In 2001, meat animals accounted for $6.7 billion in exports; dairy and eggs, $773 million.