-20.37% is the change from 491 to 391
Calculation steps:
[( 391 - 491 ) ÷ 491] x 100 = -20.37%
Formula
Percentage change = [(391 - 491) / 491] x 100
Subtract the new number by the original number
391 - 491 = -100
-100 ÷ 491 = -0.20366598778004075
-0.20366598778004075 x 100 = -20.37%