Why is the American population not negative?

There are many immigrants in America. In 20 17, the population growth rate of the United States was 0.63%, which means that the population in 20 17 increased by 0.63% compared with that in 20 16. In 20 16, the population of the United States was 323.07 million, and in 20 17, the population of the United States was 325120,000, that is, 20 17 was 2.05 million more than 20 16. However, in 20 17, the net immigrant population in the United States was as high as 4.77 million, that is to say, if there were no immigrants, the American population would have begun to grow negatively. Without a steady stream of immigrants, the United States may fall into negative population growth, and the age structure and talent structure of the population will also undergo tremendous changes.