At 7:46 ET Tuesday morning, the United States will become a nation of 300 million people, the U.S. Census Bureau estimates. Fueled by an estimated net gain of one person every 11 seconds, America -- already the world's third most populous country -- will join China and India with populations greater than 300 million, CNN reported. The main reason is simple: Births outnumber deaths. According to the Census Bureau, a child is born every seven seconds, but a death occurs every 13 seconds. But immigration also plays a role. The Census Bureau estimates that a migrant enters the country every 31 seconds. America claimed 100 million people in 1915 but didn't reach 200 million until 1967. The 400 millionth person is likely to arrive in 2043, according to the Census Bureau.
