-87.81% is the change from 320 to 39
Calculation steps:
[( 39 - 320 ) ÷ 320] x 100 = -87.81%
Formula
Percentage change = [(39 - 320) / 320] x 100
Subtract the new number by the original number
39 - 320 = -281
-281 ÷ 320 = -0.878125
-0.878125 x 100 = -87.81%