Fun fact: under 31 U.S. Code § 5117 a troy ounce of gold is still valued at 42 and 2/9ths dollars.
The countries like France that conspired in resentment to break it as ‘privilege’ are now effectively in flames.
But none of that matters here. As grandparent comment indicates, you're making a pretty fundamental math error. This is a log chart. Government may have devalued currency. It did not do so exponentially.