According to the most recent United States Census Bureau data, collected in 2013, there are 316,128,839 people in the USA. Of that population, 23.3 percent was under 18 years of age and 50.8 percent was female.
The U.S. Census Bureau’s website includes population clocks for the world and the nation, which continually count the number of people living in the world and country. According to the Bureau, America’s population grows by one person every 15 seconds. The very first U.S. census was recorded in 1790 and showed a population of 3,929,326 people. As of 2014, the world population is more than 7 billion.