-87.42% is the change from 660 to 83
Calculation steps:
[( 83 - 660 ) ÷ 660] x 100 = -87.42%
Formula
Percentage change = [(83 - 660) / 660] x 100
Subtract the new number by the original number
83 - 660 = -577
-577 ÷ 660 = -0.8742424242424243
-0.8742424242424243 x 100 = -87.42%