The Municipality of Copenhagen is by far the most populous in the country and one of the most populous Nordic municipalities with 601,448 inhabitants (). There was a demographic boom in the 1990s and first decade of the 21st century, largely due to immigration to Denmark. According to figures from the first quarter of 2016, approximately 76% of the municipality's population was of Danish descent, defined as having at least one parent who was born in Denmark and has Danish citizenship. Much of the remaining 24% were of a foreign background, defined as immigrants (18%) or descendants of recent immigrants (6%). There are no official statistics on ethnic groups. The adjacent table shows the most common countries of birth of Copenhagen residents.