683.53% is the change from 85 to 666
Calculation steps:
[( 666 - 85 ) ÷ 85] x 100 = 683.53%
Formula
Percentage change = [(666 - 85) / 85] x 100
Subtract the new number by the original number
666 - 85 = 581
581 ÷ 85 = 6.8352941176470585
6.8352941176470585 x 100 = 683.53%