-23.4% is the change from 423 to 324
Calculation steps:
[( 324 - 423 ) ÷ 423] x 100 = -23.4%
Formula
Percentage change = [(324 - 423) / 423] x 100
Subtract the new number by the original number
324 - 423 = -99
-99 ÷ 423 = -0.23404255319148937
-0.23404255319148937 x 100 = -23.4%