"Gold coins were withdrawn in 1933 and the gold standard was changed to 13.71 grains, equivalent to setting the price of 1 troy ounce of gold at $35. This standard persisted until 1968. Between 1968 and 1975, a variety of pegs to gold were put in place. The price was at $42.22 per ounce before January 1, 1975[citation needed] saw the U.S. dollar freely float on currency markets."