N.W. Ayer helped De Beers expand its sales of diamonds in the United States from a mere $23 million in 1939 to over $2 billion, at the wholesale level by 1980. In two-score years, the value of its sales had increased nearly a hundred-fold. In comparison, the expenditure on advertisements, which began at a level of only $200,000 a year and gradually increased to $10 million, seemed a prudent investment by De Beers. It had, after all, helped evolve an American diamond mind capable of absorbing the abundance of diamonds from both Africa and Siberia.