-83.12% is the change from 539 to 91
Calculation steps:
[( 91 - 539 ) ÷ 539] x 100 = -83.12%
Formula
Percentage change = [(91 - 539) / 539] x 100
Subtract the new number by the original number
91 - 539 = -448
-448 ÷ 539 = -0.8311688311688312
-0.8311688311688312 x 100 = -83.12%