-21.28% is the change from 390 to 307
Calculation steps:
[( 307 - 390 ) ÷ 390] x 100 = -21.28%
Formula
Percentage change = [(307 - 390) / 390] x 100
Subtract the new number by the original number
307 - 390 = -83
-83 ÷ 390 = -0.2128205128205128
-0.2128205128205128 x 100 = -21.28%