Post codes with the highest share of people with a foreign background in 1990 saw that proportion go from one in four to nearly half by 2010. Foreign background is defined by Statistics Sweden as a person who was either born abroad, or who has at least one foreign-born parent.
By contrast, areas with the lowest share of people with a foreign background then, around 5 percent, report almost no change.
Segregation is not bound to happen, but chances rise if public services are cut, says Roger Andersson, a professor in cultural geography. "There is a general theme of a split society and growing conflicts as a result of that," Andersson tells Swedish Radio.
The highest segregation is in the cities of Stockholm and Malmö. In areas such as Rinkeby and Rosengård more than 90 percent of residents have a foreign background.