https://www.usgs.gov/faqs/how-much-gold-has-been-found-world https://www.gold.org/goldhub/data/how-much-gold
I would take with a lot of grains of salt any "official " statistic especially when it is in relation to gold, it ain't worth the paper it is written on. The whole modern monetary system is built upon lies and deception. Like the US supposedly having over 8,000 tonnes yet it has not been allowed to be independently audited for many decades to see if it is still there. Or the Chinese and Russians only having a couple of thousand tonnes each, when anybody in the know can tell you that they both have multitudes more. Guess we will have to wait till the tide goes out of the current corrupt monetary system to see who has been swimming naked