-76.19% is the change from 420 to 100
Calculation steps:
[( 100 - 420 ) ÷ 420] x 100 = -76.19%
Formula
Percentage change = [(100 - 420) / 420] x 100
Subtract the new number by the original number
100 - 420 = -320
-320 ÷ 420 = -0.7619047619047619
-0.7619047619047619 x 100 = -76.19%