“About half of the working population in Nigeria is engaged in agriculture. Cassava is the most important food crop. Other major food crops include yam, sorghum, and maize. The share that agriculture contributes to GDP has declined from about 50 percent in 2000 to about 30 percent. Life expectancy improved between 1960 and the late 1990s, while mortality rates among children under the age of five have been declining. The number of malnourished children under five years is high (estimated at 27.2 percent in 2003). The population living on less than US$2 a day is very high (91 percent). This group is the most vulnerable to climate change because more than half depend on subsistence agriculture. The country’s population has become increasingly urban over time, and population densities are highest across southern Nigeria.”