Penn world tables version 9.0

Originally constructed by Robert Summers and Alan Heston of the University of Pennsylvania, together with the late Irving Kravis, the Penn World Tables are the definitive source for real national accounts data. The national accounts for each country, initially in their own currencies, are adjusted using detailed price data to obtain real national accounts in a common currency (U.S. dollars) across countries. These data are invaluable for making comparisons of Gross Domestic Product across countries, and for all manner of research on development and growth.