-81.39% is the change from 489 to 91
Calculation steps:
[( 91 - 489 ) ÷ 489] x 100 = -81.39%
Formula
Percentage change = [(91 - 489) / 489] x 100
Subtract the new number by the original number
91 - 489 = -398
-398 ÷ 489 = -0.8139059304703476
-0.8139059304703476 x 100 = -81.39%