The U.S. Census Bureau counted Mexicans as a separate race in 1930 .
The U.S. Census Bureau tried to retroactively determine the number of Mexicans in the U.S. in 1910 and 1920 as well .
The U.S. Census Bureau counted Mexicans as a separate race in 1930 and tried to retroactively determine the number of Mexicans in the U.S. in 1910 and 1920 as well .