From Wikipedia:

In 2001, global mine production amounted to 2,604 tonnes, or 67% of total gold demand in that year. At the end of 2001, it was estimated that all the gold ever mined totalled 145,000 tonnes.

That would make 2001's production only a 5 metre cube, and the total historical production about a 20 metre cube. Maybe the price of gold was low in 2001, and it wasn't worth making much, but that historical figure looks very low in comparison- it's only 55 years' production. Or more likely all estimates are suspect.

Don't forget its use in electrical connections and switch contacts- a thin gold plating makes a huge improvement to reliability- thereby allowing an increase of transmissible, sharable, spiritual, wealth such as Mudcat.