China has just overtaken the US as the world's biggest economy, at least when the figures are adjusted for Purchasing Power Parity or PPP.
According to the International Monetary Fund, the combined purchasing power of China's citizens now outstrips that of America's.
The IMF also says that by the end of the year China will make up 16.5% of the world's purchasing-power adjusted GDP for a total of over 17.6 trillion US dollars.
The US, by contrast, will make up 16.3%, or $17.4 trillion.
Measuring GDP based on Purchasing Power Parity takes in to account the cost of living in individual countries rather than just their GDP per capita -- by comparing the cost of a basket of goods from one country to another.
IMF Chief Christine Lagarde acknowledges that GDP based on PPP was one way of measuring China's economic strength but other factors need to be considered.
"You know, it's one indicator amongst many others. If you look at GDP per capita, China is way behind of course. But you have to take all the factors into account, to actually assess the stability and future of an economy. I wouldn't neglect demographics by the way. So it's a sign that by that particular criteria, China is growing."
China's Vice Finance Minister Zhu Guangyao earlier said in Washington D.C. that China is still a developing country and still lags behind the U.S. in terms of economic growth quality.
