Loading ...I think it was down to 20% backed when Nixon abandoned the idea. I tend to think Keynes was right when he called the gold standard “that barbarous relic”. It meant a lot to people only because they didn’t understand it. they thought they could take paper dollars into the bank and get gold, but that could never have been allowed to happen on any significant basis as there was never enough.
That’s (the barbarous relic bit) not the same as having gold reserves though. Countries keep foreign currency reserves in many formats, cash, foreign bonds (mainly foreign govt but they could hold company debt) and gold/silver. You could have enough gold equivalent to 20% of your currency in circulation and not refer to the currency as being gold backed, but you would still have substantial reserves which cannot be devalued or cancelled.