In 2015 there were 2,048,700 foreign nationals with permanent residency (meaning those granted a permit for 12 months or longer) in the country, just under a quarter (24.6 percent) of the total population, said the Swiss statistics office (SS).
That's up from 1,998,500 in 2014.
The 2015 figure includes 393,600 people who were born in Switzerland but do not have Swiss citizenship, with the rest being foreign-born immigrants.
Of those born outside Switzerland, 44 percent have lived here for ten years or more.
The biggest foreign populations are Italians, Germans, Portuguese, French and Kosovans, which make up more than half (54 percent) of permanent foreign residents in Switzerland.
Geneva has the highest number of foreigners, at 41 percent, followed by the cantons of Basel-City (35 percent) and Vaud (34 percent).
Some 2.1 percent of foreigners obtained Swiss citizenship in 2015, said SS, though Geneva's figure was higher, at 3.6 percent.
The percentage of foreigners in Switzerland has grown continually. Source: SS
In total, the population of Switzerland grew by 1.1 percent in 2015, to 8,327,100.
That's slightly less growth than in the previous two years, when the population expanded by 1.3 percent (2013) and 1.2 percent (2014).
In terms of migration (of both Swiss and foreigners), 188,500 people arrived to live in the country in 2015 and 116,600 left.
While migration was a big factor in the population growth, “It must be noted however that natural growth – meaning the difference between births and deaths – also contributed to the increase in the Swiss population,” said the SS in a statement.
The country registered 86,600 births and 67,600 deaths in 2015.
That's in contrast to many European countries, including Germany, Italy and Portugal, where deaths outweighed births, it said.
The cantons of Zug, Vaud and Geneva saw their populations increase slightly more than the average, while Neuchâtel and Graubünden had only 0.4 percent growth.
Uri was the only canton to see a decrease in its population.