Golden Debuggery

Ezra has an interesting post about why people buy gold.  This fact stands out:

According to the World Gold Council, only 166,600 tons of gold have been mined since the beginning of civilization – all of which would fit into a crate of 20 meters cubed.

So I did some quick math:
(166,600 tons of gold)* (2,000 pounds / ton) = 333,200,000 pounds of gold
(333,200,000 pounds of gold) * (16 ounces / pound) = 5,331,200,000 ounces of gold
(5,331,200,000 ounces of gold) * ($1662.31 / ounce) = $8,862,107,072,000.00

The US GNP = 14,561,700,000,000.00.

I know this isn't an original observation but it is worth repeating. There is not enough gold in the world to cover the U.S. GNP for a year. How exactly are we supposed to convert to the "gold standard"?