On May 22, 2013, Forbes magazine reported that Bill Gates had overtaken Mexican businessman Carlos Slim as the "richest man in the world." Gates's fortune on that date was estimated at $70 billion, whereas Slim's was a mere $69.86 billion. (http://www.forbes.com/sites/erincarlyle/2013/05/22/bill-gates-is-worlds-richest-bumpsslim/) Does this make Gates the richest American who ever lived? John D. Rockefeller, the founder of Standard Oil, is usually credited with this distinction. At the time of his death in 1937, the founder of the Standard Oil empire had an estimated net worth of $1.4 billion.

Some analysts say that Rockefeller's net worth was economically equivalent to approximately $x billion today. This figure is arrived at in a particular way. First, his net worth in 1937 is calculated as a percentage of total U.S. GDP in 1937. That percentage is then multiplied by the current level of GDP to arrive at the equivalent figure in current dollars. You can find the relevant GDP figures at http://research.stlouisfed.org/fred2/data/GDPA.txt. Compute x. (Show your calculations.) (5 points)