I want to know the answer to the following question:
How much money has the sale of Federal Duck Stamps generated since 1934?
All the background I'm provided with is that "Since 1934, the sale of Federal Duck Stamps has generated $670 million, and helped to purchase or lease 5,200,000 acres (8,100 sq mi; 21,000 km2) of habitat.". Is that enough to answer the question?