Society and culture in English-speaking countries II. Why is the United States called "the country of immigrants"?

Historically, the United States is a country founded by immigrants. When Europeans exiled criminals to America, they began to emigrate to North America. The famous Mayflower brought the Puritans to the North American continent and began to colonize. After the rise of plantations in the southern United States, a large number of African blacks were sold to the United States; When the railway was built in the north, Asian laborers set foot on the American continent. At the beginning of the founding of the United States, the total population of the country was only 3.9 million, of which about 760,000 were black, and almost all others were white, mostly from Western Europe. After more than 200 years of development, the United States has a very diverse race and nation. By 20 18, the population of the United States will reach 327 million, of which 62. 1% is European, 7.4% is Hispanic, 3.2% is African-American, 5.4% is Asian and 2.5% is mixed-race.