In 2007, 138,961 twins were born in the United States. This represented 3.2 percent of all live births (a birth ratio of 32.2 per 1,000 births). There were 5,967 triplet births, 369 quadruplet births, and 91quintuplets and other higher order births in 2007. The birth rate for triplets or higher-order multiple births was 148.9 per 100,000 live births.