To "preserve the ideal of American homogeneity", the Emergency Quota Act of 1921 (numeric limits) and the Immigration Act of 1924 (fewer southern and eastern Europeans) restricted admission to the United States according to the skin color and the race of the immigrant. In practice, the Emergency Quota Act used outdated census data to determine the number of colored immigrants to admit to the U.S. To protect WASP ethnic supremacy (social, economic, political) in the 20th century, the Immigration Act of 1924 used the twenty-year-old census of 1890, because its 19th-century demographic-group percentages favored more admissions of WASP immigrants from western and northern Europe, and fewer admissions of colored immigrants from Asia and southern and eastern Europe.