Europe, 1989
Europe Council, 1989: During the last half of the 20th Century, demographers economists, political scientists and others have studied the relationship, or more accurately, the inter-relationship among population growth, GDP, per capital income and a host of other variables. They have generally concluded that the more advanced a nation, in terms of its agricultural productivity, industrial base, social and educational systems and political structures and institutions, the more its individuals self-regulate family size.