-81.43% is the change from 490 to 91
Calculation steps:
[( 91 - 490 ) ÷ 490] x 100 = -81.43%
Formula
Percentage change = [(91 - 490) / 490] x 100
Subtract the new number by the original number
91 - 490 = -399
-399 ÷ 490 = -0.8142857142857143
-0.8142857142857143 x 100 = -81.43%