The Maddison Project Database was started in March 2010. The project builds on the original dataset created by economist Agnus Maddison to revise or adjust the historical economic data based on new information. Data for population, GDP, and per capita GDP are presented by countries, small country groups, regions, and the world, dating back to Roman times. In the January 2013 update many of the pre-1820 and all of the pre-1600 numbers for GDP per capita were modified.