Which countries have the most immigrants?

The United States has the highest number of immigrants (foreign-born individuals), with 48 million in 2015, five times more than in Saudi Arabia (11 million) and six times more than in Canada (7.6 million). However, in proportion to their population size, these two countries have significantly more immigrants: 34% and 21%, respectively, versus 15% in the United States. Small countries have higher proportions of immigrants. With 29% of immigrants, Switzerland is ahead of the United States and France, while the proportion in Luxembourg is even higher (46%)