Nigeria, Africa’s second-largest economy, has been one of the continent’s most consistent performers in recent years, with annual gross domestic product increases of between 5% and 8% since 2003. Ranked 30th in the world, Nigeria is the United States' largest trading partner in sub-Saharan Africa and supplies a fifth of its oil (11% of oil imports). Earmarked as soon becoming the largest economy in Africa, it is worth your while to keep an eye on this country.