-20.81% is the change from 620 to 491
Calculation steps:
[( 491 - 620 ) ÷ 620] x 100 = -20.81%
Formula
Percentage change = [(491 - 620) / 620] x 100
Subtract the new number by the original number
491 - 620 = -129
-129 ÷ 620 = -0.20806451612903226
-0.20806451612903226 x 100 = -20.81%