-21.79% is the change from 390 to 305
Calculation steps:
[( 305 - 390 ) ÷ 390] x 100 = -21.79%
Formula
Percentage change = [(305 - 390) / 390] x 100
Subtract the new number by the original number
305 - 390 = -85
-85 ÷ 390 = -0.21794871794871795
-0.21794871794871795 x 100 = -21.79%