Answer :
They came mostly from Latin America and Asia. I know this because during that time the war in south Korea was going on and a lot of immigrants from that area came flooding in trying to get away from the war. Hope I helped. :)
The answer is Latin America and Asia. Europeans came to America hundreds of years ago and few people are coming over since. Asia is more broad that Vietnam and includes China and India, countries that have a combined population that is around two fifths of the whole population. So it's Latin America and Asia. Hope this helps!