Nigeria has raced past South Africa to become Africa's biggest economy, after the government recalibrated its measures for calculating gross domestic product (GDP.)

Nigeria now boasts the 26<sup>th largest economy in the world, after its GDP nearly doubled in size as a result of the changes.

According to the new statistics, Nigeria's GDP was $509.9bn (£307.6bn, €371.4) during 2013, nearly 90% higher than the previous figures and higher than South Africa's $370.3bn posted in 2013.

The national GDP has been rebased and now includes fast-growing industries like telecoms, information technology, airlines, film production and online sales.

However, Nigeria doesn't beat its regional rival on all fronts, even with the revision. When taking the size of each country's population into account, the figures of GDP per-capita favours South Africa.

With its population of 170m, three-times the size of South Africa's, Nigeria's GDP per-head is three-times smaller than South Africa's. That could suggest that the Nigerian economy is actually underperforming.

It is also worth noting that most countries rebase their GDP every few years, whereas Nigeria hadn't undertaken the updates in more than two decades. In that period, a number of new industries have boomed and largely explain the near-doubling of the Nigerian GDP.

The changes push Nigeria towards its target of entering the 20 biggest economies in the world. Moreover, it could act as a spur to attract foreign investment. Africa's leading oil-producer is already awash with foreign companies but the latest figures could encourage more money to flow into the country as a result.

The new figures have also drastically changed the picture of Nigeria's economy.

Oil and gas used to make up a third of the economy but only contribute 15% of the economy in the new figures. Meanwhile the country's film industry known as Nollywood has been recognised for the first time and makes up 1.4% of the country's GDP.

Moreover, the reappraisal is likely to hurt the country's current account deficit and slow down the growth rate.

The new figures were endorsed by the International Monetary Fund, the World Bank and the African Development Bank over the past three months.