The Migration and Remittances Factbook 2011 updates the 2008 edition of the Factbook with additional data for 71 countries collected from various sources, including national censuses, labor force surveys, population registers, and other national sources. The Factbook attempts to present numbers and facts behind the stories of international migration and remittances, drawing on authoritative, publicly available data. It provides a snapshot of statistics on immigration, emigration, skilled emigration, and remittance flows for 210 countries and 15 regional and income groups. Some interesting facts emerge:•More than 215 million people, or 3 percent of the world population, live outside their countries of birth. Current migration flows, relative to population, are weaker than those of the last decades of the nineteenth century.•The top migrant destination countries are the United States, the Russian Federation, Germany, Saudi Arabia, and Canada. The top immigration countries, relative to population, are Qatar (87 percent), the United Arab Emirates (70 percent), Kuwait (69 percent), Andorra (64 percent), Cayman Islands (63 percent), and Northern Mariana Islands (62 percent).•The United States is likely to have seen the largest inflows of migrants between 2005 and 2010, despite the global financial crisis. The expansion of the European Union led to a surge of migrant flows to Spain, Italy, and the United Kingdom, with a large share from Eastern Europe. •The six Gulf Cooperation Council countries (Saudi Arabia, United Arab Emirates, Bahrain, Qatar, Oman, and Kuwait) have also seen a significant increase in migrant flows in the last few years, mostly from South Asia and East Asia. However, immigrant stocks in all regions started to plateau in 2009-10 because of the global financial crisis. •The volume of South-South migration is larger than migration from the South to the high-income countries belonging to the Organization of Economic Cooperation and Development (OECD). High-income non-OECD countries such as the Gulf countries are also major destinations for migrants from the South. South-South migration is significantly larger than South-North migration in Sub-Saharan Africa (73 percent) and Europe and Central Asia (61 percent). •According to available official data, the Mexico-United States corridor is the largest migration corridor in the world, accounting for 11.6 million migrants in 2010. Migration corridors in the Former Soviet Union - Russia-Ukraine, and Ukraine-Russia - are the next largest, followed by Bangladesh-India. In these corridors, natives became migrants without moving when new international boundaries were drawn.