-23.99% is the change from 421 to 320
Calculation steps:
[( 320 - 421 ) ÷ 421] x 100 = -23.99%
Formula
Percentage change = [(320 - 421) / 421] x 100
Subtract the new number by the original number
320 - 421 = -101
-101 ÷ 421 = -0.23990498812351543
-0.23990498812351543 x 100 = -23.99%