and national origins of legal immigration since 1965. U.S. citizens and Lawful Permanent Residents (or "Green card" holders) may petition for visas for their immediate relatives including their children, spouses, parents, or siblings. Advocates of immigration restriction believe the family reunification policy is too permissive, leads to higher than expected levels of immigration, and what they consider the wrong type of immigrants. In its place, they favor increasing the number of immigrants with particular job skills. In practice, however, the wait times from when a family reunification petition is filed until the adult relative is able to enter the U.S. can be as long as 15–20 years (as of 2006). This is a result of backlogs in obtaining a visa number and visa number quotas that only allow 226,000 family-based visas to be issued annually. There are four family-based preference levels, data valid as of June 2009: Unmarried Sons and Daughters of Citizens: 23,400 plus any numbers not required for fourth preference. Spouses and Children, and Unmarried Sons and Daughters of Permanent Residents: 114,200, plus the number (if any) by which the worldwide family preference level exceeds 226,000, and any unused first preference numbers: A. Spouses and Children: 77% of the overall second preference limitation, of which 75% are exempt from the per-country limit; B. Unmarried Sons and Daughters (21 years of age or older): 23% of the overall second preference limitation. Third: Married Sons and Daughters of Citizens: 23,400, plus any numbers not required by first and second preferences. Fourth: Brothers and Sisters of Adult Citizens: 65,000, plus any numbers not required by first three preferences. Backlogs in obtaining visa numbers range from four-and-a-half years (for preference level 2A) to 23-years (for preference level 4 immigrants from the Philippines). While some backlogs have remained relatively steady for some time, since 1995, backlogs for other family-sponsored preferences have steadily increased (see image to the right). During the debate on immigration policy following Donald Trump's rescission of the Deferred Action for Childhood Arrivals program, the term "chain migration" became contentious. In 2018, The Associated Press Stylebook was updated to discourage use of the term, describing it as being "applied by immigration hardliners to what the U.S. government calls family-based immigration". See also Immigration reduction Immigration reform K-1 visa References Further reading Alexander, June Granatir. "Chain Migration and Patterns of Slovak Settlement in Pittsburgh Prior to World War I". Journal of American