-20.9% is the change from 531 to 420
Calculation steps:
[( 420 - 531 ) ÷ 531] x 100 = -20.9%
Formula
Percentage change = [(420 - 531) / 531] x 100
Subtract the new number by the original number
420 - 531 = -111
-111 ÷ 531 = -0.20903954802259886
-0.20903954802259886 x 100 = -20.9%