Immigration to the United States has been a major source of population growth and cultural change throughout much of its history. In absolute numbers, the United States has by far the highest number of immigrant population in the world, with 50,661,149 people as of 2019. This represents 19.1% of the 244 million international migrants worldwide, and 14.4% of the United States' population. In 2018, there were almost 90 million immigrants and U.S.-born children of immigrants in the United States, accounting for 28% of the overall U.S. population. According to the 2016 Yearbook of Immigration Statistics, the United States admitted a total of 1.18 million legal immigrants (618k new arrivals, 565k status adjustments) in 2016. Of these, 48% were the immediate relatives of United States citizens, 20% were family-sponsored, 13% were refugees or asylum seekers, 12% were employment-based preferences, 4.2% were part of the Diversity Immigrant Visa program, 1.4% were victims of a crime (U1) or their family members were (U2 to U5), and 1.0% who were granted the Special Immigrant Visa (SIV) for Iraqis and Afghans employed by the United States Government. The remaining 0.4% included small numbers from several other categories, including 0.2% who were granted suspension of deportation as an immediate relative of a citizen (Z13); persons admitted under the Nicaraguan and Central American Relief Act; children born after the issuance of a parent's visa; and certain parolees from the former Soviet Union, Cambodia, Laos, and Vietnam who were denied refugee status. Between 1921 and 1965, policies such as the national origins formula limited immigration and naturalization opportunities for people from areas outside Northwestern Europe. Exclusion laws enacted as early as the 1880s generally prohibited or severely restricted immigration from Asia, and quota laws enacted in the 1920s curtailed Southern and Eastern European immigration. The civil rights movement led to the replacement of these ethnic quotas with per-country limits for family-sponsored and employment-based preference visas.