2005 OECD report: Increasing the average schooling level of the population by one year increases long-term economic growth by 3.7%

From The Flat World and Education: How America’s Commitment To Equity Will Determine Our Future, a forthcoming 2010 book by Stanford professor and Obama education adviser Linda Darling-Hammond:

A recent OECD report found that for every year the average schooling level of the population is raised, there is a corresponding increase of 3.7% in long-term economic growth.