Nigeria is the biggest country in Africa in terms of population: more than 180 million
Population density is highest in the south, where there are many big cities and job opportunities, as well as plantations growing tropical products like cocoa and palm oil for export
Central and northern Nigeria are drier and less densely populated, with a few big cities like Kano, the trading centre of northern Nigeria
Population density is low in the savannah outside the cities, where people are mostly farmers growing yams, cassava, peanuts and grain
In the steppes the only viable form of agriculture is livestock farming, which is the most sparsely populated part of the region
GNP per head of population is higher in the south than in the north, and incomes are lowest in rural regions where most farms are small and produce very little