-88.57% is the change from 866 to 99
Calculation steps:
[( 99 - 866 ) ÷ 866] x 100 = -88.57%
Formula
Percentage change = [(99 - 866) / 866] x 100
Subtract the new number by the original number
99 - 866 = -767
-767 ÷ 866 = -0.8856812933025404
-0.8856812933025404 x 100 = -88.57%