Migrants who move from lower to higher income economies are often able to gain an income that is 20 or 30 times higher than they would be able to gain at home. Migrants who move from lower to higher income economies are often able to gain an income that is 20 or 30 times higher than they would be able to gain at home. the World Bank estimates that the annual value of formally transferred remittances in 2004 was about $ 150 billion, representing a 50 per cent increase in just five years.