The routine of increasing the white population in the United States adds points.

The immigration tide in the United States, with no less than 50 million immigrants, plus good fertility and living conditions at that time. In addition, the death toll is much less than that of European countries, especially the Soviet Union and Germany, which may be less than 500,000. In this way, the population base is more than that of European countries 1 100 million. Coupled with people's long life span, besides, the population of European countries adds up to a lot. That seems reasonable.