-7.8% is the change from 423 to 390
Calculation steps:
[( 390 - 423 ) ÷ 423] x 100 = -7.8%
Formula
Percentage change = [(390 - 423) / 423] x 100
Subtract the new number by the original number
390 - 423 = -33
-33 ÷ 423 = -0.07801418439716312
-0.07801418439716312 x 100 = -7.8%