By Tom Jackson
While north African countries such as Morocco, Algeria and Egypt receive the most, east African countries are particularly dependent on remittances.
The average per migrant is almost $1,200, representing 5% of GDP on a country-by-country average.
Yet the cost of sending this money is high.
The Overseas Development Institute (ODI) reports Africans in the diaspora pay an average of 12.3% to money transmitters to send $200 home, while the cost of sending money between African countries is also high. Each year, the ODI says total fees amount to $1.4bn.
Part of the reason for these high costs could be a lack of competition; Western Union and MoneyGram control 50% or more of the remittance market in most Sub-Saharan African countries. But help may be at hand from an unlikely source: digital currency Bitcoin.