The end of immigration quotas in the 1960s led to

The Immigration Act of 1965 ended the earlier quota system based on natural origin. In the earlier quota system, each nationality was assigned a quota or a maximum number of people of a particular nationality allowed into the USA. The new Immigration Act specified a new policy which was based on reuniting immigrant families and inviting skilled labor to the United States of America. This changed the demographics of the population as many of the new immigrants came from countries in Asia, Africa, and South America.