system for certain relatives of U.S. residents, including their unmarried children under 21, their parents, and spouses at least 21 and over. It also preferred immigrants at least 21 who were skilled in agriculture and their wives and dependent children under 16. Non-quota status was accorded to wives and unmarried children under 18 of U.S. citizens; natives of Western Hemisphere countries, with their families; non-immigrants; and certain others. Subsequent amendments eliminated certain elements of the law's inherent discrimination against women. Quota calculation formula In 1927, the 1924 act was modified to use census data from 1920. The Bureau of the Census and Department of Commerce estimated the National Origins of the White Population of the United States in 1920 in numbers, then calculated the percentage share each nationality made up. The National Origins Formula derived quotas by calculating the equivalent proportion of each nationality out of a total pool of 150,000 annual quota immigrants, with a minimum quota of 100. This formula was used until the Immigration and Nationality Act of 1952 adopted a simplified formula limiting each country to a flat quota of one-sixth of one percent of that nationality's 1920 population count, with a minimum quota of 100. Quotas by country under successive laws Listed below are historical quotas on emigration from the Eastern Hemisphere, by country, as applied in given fiscal years ending June 30, calculated according to successive immigration laws and revisions from the Emergency Quota Act of 1921 to the final quota year of 1965. The 1922 and 1925 systems based on dated census records of the foreign-born population were intended as temporary measures; the 1924 Act's National Origins Formula based on the 1920 census of the total U.S. population took effect on July 1, 1929. Visas and border control The act also established the "consular control system" of immigration, which divided responsibility for immigration between the U.S. State Department and the Immigration and Naturalization Service. The act also mandated no alien to be allowed to enter the United States without a valid immigration visa issued by an American consular officer abroad. Consular officers were now allowed to issue visas to eligible applicants, but the number of visas to be issued by each consulate annually was limited, and no more than 10% of the quota could be given out in any one month. Aliens were not able to leave their home countries before having a