-89.23% is the change from 390 to 42
Calculation steps:
[( 42 - 390 ) ÷ 390] x 100 = -89.23%
Formula
Percentage change = [(42 - 390) / 390] x 100
Subtract the new number by the original number
42 - 390 = -348
-348 ÷ 390 = -0.8923076923076924
-0.8923076923076924 x 100 = -89.23%