Remittances - people sending money from abroad to their families back home - are one of the biggest sources of income in Africa. There's an interesting article in the Financial Times about this, as well as beautiful graphics in the New York Times. The New York Times graphic shows that the amount of remittances sent to The Gambia in 2005 as a percentage of the GDP was about 11.44% (more than Senegal's 6.85%). This is not surprising, as a lot of families over here depend on the monthly allowances sent from abroad, to keep afloat from month-to-month. (As a result, the strengthening of the dalasi against the dollar is a mixed blessing: it may mean reduced prices in the future, but it also means the dollar allowances sent do not stretch as far).
Another interesting graphic from the NY Times article is the one showing the percentage of countries' populations abroad. There are apparently over 15% of the Gambian population in another country (compared, again, to Senegal's 2.8%). Again, this is not surprising, as most youth (who comprise the majority of the population of The Gambia) are interested in one thing only when they finish school: getting out of here. In fact the percentage leaving would be much higher if it weren't for the overly strict visa laws that govern travel to almost all European countries and the US.