In response to this article, I've posted data I've collected on gold-to-GDP.
This chart aims to measure risk, in that gold would rise relative to GDP in times of dollar risk. The benchmark is 1933-1934, when the government intervened on behalf of the dollar by manipulating gold spot - back then, it was an adjustment to gold spot when gold was still regarded as money; today, government intervention utilizing gold would be akin to dollar default and replacing it with gold. During 1933-1934, the gold-to-GDP ratio was 0.138.
As you can see, in 1980, the ratio was less than half that, and today, it is about 1/6 that.
Disclosure: Author is long GLD LEAPs