The United States has witnessed a surge in immigration over the last half-century. In 1970, foreign-born individuals made up 4.7% of the population. This number has almost tripled since, standing now at 13%. New immigration, plus births to immigrants, added more than 22 million people to the U.S. population in the last decade, equal to 80% of total population growth. Approximately one in four children under 18 now have at least one foreign-born parent. Not since the early 20th century have the foreign-born made up such a large proportion of the United States’ population.