With the data being for the UK 0.92 years in 1870, 6.24 years in 1940, 7.01 years in 1960, 9.97 years in 2000 and 12.46 years in 2010. Since 1960 that's a rise of 0.109 years per year. If the return to education is 7% and the share of labour in value added is 0.66, that's a contribution to GDP growth of 0.005, that is, 0.5pppa. GDP growth was, 1960-2010, 2.6%.
