-7.13% is the change from 421 to 391
Calculation steps:
[( 391 - 421 ) ÷ 421] x 100 = -7.13%
Formula
Percentage change = [(391 - 421) / 421] x 100
Subtract the new number by the original number
391 - 421 = -30
-30 ÷ 421 = -0.07125890736342043
-0.07125890736342043 x 100 = -7.13%