He has been member of the Royal Netherlands Academy of Arts and Sciences since 1980 .
From 1978 to 1985 he was the first chairman of the Washington - based economics body , the Group of Thirty .
chairman has been chairman of the Royal Netherlands Academy of Arts and Sciences since 1980 .
From 1978 to 1985 he was the first chairman of the Washington - based economics body , the Group of Thirty .