Historical data for the last fifty years shows that there is a surprisingly strong correlation between the growth rate of a nation’s GDP per person and its income level. The growth rate declines linearly with income, and this relationship can be used to estimate the future growth rate of a nation’s economy. Using the same method it is also possible to forecast the share of GDP in agriculture, industry, and services – and to demonstrate the continuing decline of the share in industry as a nation get very rich. This article concludes with a discussion of the likely impact of robotisation and greening on GDP growth.