Very little trickles down. Nigeria, like so many countries in Africa, is patently not a developing nation. It is underdeveloping. Its people are far worse off now than they were thirty years ago. The numbers speak for themselves.
Literacy is below that of the Democratic Republic of Congo.
Gross domestic product per person is lower now than it was before the beginning of the oil boom of the 1970s. To even return to the living standards of that time, the economy would have to grow by an unlikely 5 percent per year until 2010. The World Bank ranks Nigeria as the thirteenth poorest country in the world. The 1999 UN human development index gives it a slightly better though still disheartening score, 146th out of 174. So far the West has done little to help and has often made matters worse.