1970
Two tiers, window still open
In 1970 the Gold Pool has already collapsed. The free price can leave $35. The official window for foreign treasuries closes on 15 August 1971.
Since March 1968 there have been two prices: an official price for central banks, and a free-market price. The pool is not reconstituted.
Foreign official holders can still convert dollars into gold at the Treasury. That window closes on 15 August 1971. Private holding of monetary gold is still restricted.