Of them, 90,250 were from Africa and 13,710 from Europe.The global volume of immigration is high in absolute terms, but low in relative terms.The modern idea of immigration is related to the development of nation-states and nationality law.The European Union allows free movement between member states.This accounts for almost 85% of Europe's total population growth in 2005.In 2005, immigration fell slightly to 135,890.In recent years, immigration has accounted for more than half of Norway's population growth.British emigration towards Southern Europe is of special relevance.Citizens from the European Union make up a growing proportion of immigrants in Spain.Theories of immigration traditionally distinguish between push factors and pull factors.