-26.43% is the change from 420 to 309
Calculation steps:
[( 309 - 420 ) ÷ 420] x 100 = -26.43%
Formula
Percentage change = [(309 - 420) / 420] x 100
Subtract the new number by the original number
309 - 420 = -111
-111 ÷ 420 = -0.2642857142857143
-0.2642857142857143 x 100 = -26.43%