Migrants to OECD countries come from a wide variety of sending countries, with different migration behaviour and varied migration histories. Transition countries, the most important source of migrants for OECD countries in Europe, are characterised by explosive
emigration and painful economic adjustments. Emigration from sub‐Saharan Africa, meanwhile, continues a long history of mobility within Africa in search of a better livelihood. Generally, low‐skilled African migrants go to other African countries
and Europe; the highly skilled go to North America, reflecting migration policies in receiving countries. The transition from exporter to importer of migrants demonstrates a country's economic progress. For example, Poland now has an influx of highly skilled
workers from Western countries. Guatemalan migrants in Mexico, in contrast, demonstrate an essentially circular, seasonal pattern of migration, though new patterns are emerging there.