Out-migration

Human migration is the movement by people from one place to another with the intentions of settling, permanently in the new location. The movement is often over long distances and from one country to another, but internal migration is also possible; indeed, this is the dominant form globally. Migration may be individuals, family units or in large groups.

Nomadic movements are normally not regarded as migrations as there is no intention to settle in the new place and because the movement is generally seasonal. Only a few nomadic people have retained this form of lifestyle in modern times. Also, the temporary movement of people for the purpose of travel, tourism, pilgrimages, or the commute is not regarded as migration, in the absence of an intention to live and settle in the visited places.

Many estimates of statistics in worldwide migration patterns exist.

The World Bank has published its Migration and Remittances Factbook annually since 2008. The International Organisation for Migration (IOM) has published a yearly World Migration Report since 1999. The United Nations Statistics Division also keeps a database on worldwide migration. Recent advances in research on migration via the Internet promise better understanding of migration patterns and migration motives.

Substantial internal migration can also take place within a country, either seasonal human migration (mainly related to agriculture and to tourism to urban places), or shifts of population into cities (urbanisation) or out of cities (suburbanisation). Studies of worldwide migration patterns, however, tend to limit their scope to international migration.

The World Bank's Migration and Remittances Factbook of 2011 lists the following estimates for the year 2010: total number of immigrants: 215.8 million or 3.2% of world population. In 2013, the percentage of international migrants worldwide increased by 33% with 59% of migrants targeting developed regions. Almost half of these migrants are women, which is one of the most significant migrant-pattern changes in the last half century. Women migrate alone or with their family members and community. Even though female migration is largely viewed as associational rather than independent migration, emerging studies argue complex and manifold reasons for this.

...
Wikipedia