<Tr> <Th> Foreign reserves </Th> <Td> $42.8 billion (2012) </Td> </Tr> <Tr> <Td_colspan="2"> Main data source: CIA World Fact Book All values, unless otherwise stated, are in US dollars . </Td> </Tr> <P> Nigeria is a middle - income, mixed economy and emerging market, with expanding manufacturing, financial, service, communications, technology and entertainment sectors . It is ranked as the 21st - largest economy in the world in terms of nominal GDP, and the 20th - largest in terms of purchasing power parity . It is the largest economy in Africa; its re-emergent manufacturing sector became the largest on the continent in 2013, and it produces a large proportion of goods and services for the West African subcontinent . In addition, the debt - to - GDP ratio is 11 percent, which is 8 percent below the 2012 ratio . </P> <P> Previously hindered by years of mismanagement, economic reforms of the past decade have put Nigeria back on track towards achieving its full economic potential . Nigerian GDP at purchasing power parity (PPP) has almost tripled from $170 billion in 2000 to $451 billion in 2012, although estimates of the size of the informal sector (which is not included in official figures) put the actual numbers closer to $630 billion . Correspondingly, the GDP per capita doubled from $1400 per person in 2000 to an estimated $2,800 per person in 2012 (again, with the inclusion of the informal sector, it is estimated that GDP per capita hovers around $3,900 per person). (Population increased from 120 million in 2000 to 160 million in 2010). These figures were to be revised upwards by as much as 80% when metrics were to be recalculated subsequent to the rebasing of its economy in April 2014 . </P>

What is the structure of the nigerian economy