According to the data of Chinese Internet data network, the total population of the United States reached 328 million in 20 19, ranking third in the world. However, from 20 18 to 20 19, the population only increased by 0.5%, about15 million. The United States is the only developed country in the world where the population is still growing at a rapid rate, which enables the United States to maintain the momentum of rapid growth in production and consumption for a long period of time, and makes the quantitative aspect of American national strength show a sustained development and upward trend.