OECD countries accounted for around 50% of the world’s Gross Domestic Product (GDP) expressed in Purchasing Power Parities (PPPs) in 2011 - the latest benchmark year - compared with about 60% in 2005, the previous benchmark year, according to new data released by the International Comparison Program (ICP).

Large emerging economies (China, Brazil, India, Indonesia, the Russian Federation and South Africa) together accounted for around 30% of the world’s GDP in 2011, compared with about 20% in 2005. In 2011, the three largest economies in the world were the United States (17.1%), China (14.9%) and India (6.4%).

Shares in world GDP in PPPs, 2011 (%)

The ICP is the largest worldwide statistical partnership involving some 200 countries and regional agencies. It collects internationally comparable prices and estimates volume measures for gross domestic product and its components based on PPPs.

The OECD is a partner in the ICP. Together with Eurostat, it calculated new 2011 benchmark PPPs for GDP and final consumption for 47 countries. These benchmark results were included in the world-wide ICP comparison.

PPPs are the relevant currency conversion rates to make international comparisons of economic activity. Unlike exchange rates, they correct for differences in price levels across countries. As price levels are high in higher income countries and low in lower income countries, a comparison based on exchange rate conversion overstates the size of high-income countries and under-states the size of lower income countries. For instance, expressed using exchange rates, the OECD area’s GDP accounted for two thirds of the world’s GDP, as opposed to about half when PPPs are used (see table).