-86.73% is the change from 686 to 91
Calculation steps:
[( 91 - 686 ) ÷ 686] x 100 = -86.73%
Formula
Percentage change = [(91 - 686) / 686] x 100
Subtract the new number by the original number
91 - 686 = -595
-595 ÷ 686 = -0.8673469387755102
-0.8673469387755102 x 100 = -86.73%