The abolition of the National Origins quota system came with the Hart–Celler Act of 1965. This legislation placed a heavy emphasis on family reunification, designating 74% of visas for that purpose. There was no limit on spouses, unmarried minor children, and parents of U.S. citizens. The percentages for family reunification were as follows: Unmarried adult children of U.S. citizens (20%), spouses and unmarried children of permanent residents aliens (20%), married children of U.S. citizens (10%), brothers and sisters of U.S. citizens over age 21 (24%). These new visa preferences created a swell of new chain migration and immigration in general. The Third World began to outpace European immigration to America for the first time in history, surpassing it by the end of the 1960s and doubling the numbers of European migration by the end of the 1970s.