Immigration is the movement of people into a different country in order to settle there. Immigration is made for many reasons, including temperature, breeding, economic, political, family re-unification, natural disaster, poverty or the wish to change one's surroundings voluntarily.
As of 2006, the International Organization for Migration has estimated the number of foreign migrants worldwide to be more than 200 million. Europe hosted the largest number of immigrants, with 70 million people in 2005. North America, with over 45 million immigrants, is second, followed by Asia, which hosts nearly 25 million. Most of today's migrant workers come from Asia.
In 2005, the United Nations reported that there were nearly 191 million international migrants worldwide, about 3 percent of the world population. This represented a rise of 26 million since 1990. 60 percent of these immigrants were now in developed countries, an increase on 1990. Those in less developed countries stagnated, mainly because of a fall in refugees. Contrast that to the average rate of globalization (the proportion of cross-border trade in all trade), which exceeds 20 percent. The numbers of people living outside their country of birth is expected to rise in the future.
The Midwestern United States, some parts of Europe, some small areas of Southwest Asia, and a few spots in the East Indies have the highest percentages of immigrant population recorded by the UN Census 2005. The reliability of immigrant censuses is low due to the concealed character of undocumented labor migration.