Limited immigration from outside the Western part of the world.
Each country would send 3% of the amount of people of that Nation already living in the USA per year. (in 1920)
Reduced amount of immigrants allowed from outside of the Western part of the world to 164,000 per year.
290 people from each nation (of nations in which there were already people from them living in the USA since 1890)
Very few allowed in when quota was reduced again to allow only 150,000