-81.69% is the change from 497 to 91
Calculation steps:
[( 91 - 497 ) ÷ 497] x 100 = -81.69%
Formula
Percentage change = [(91 - 497) / 497] x 100
Subtract the new number by the original number
91 - 497 = -406
-406 ÷ 497 = -0.8169014084507042
-0.8169014084507042 x 100 = -81.69%