-91.59% is the change from 666 to 56
Calculation steps:
[( 56 - 666 ) ÷ 666] x 100 = -91.59%
Formula
Percentage change = [(56 - 666) / 666] x 100
Subtract the new number by the original number
56 - 666 = -610
-610 ÷ 666 = -0.9159159159159159
-0.9159159159159159 x 100 = -91.59%