-39.06% is the change from 128 to 78
Calculation steps:
[( 78 - 128 ) ÷ 128] x 100 = -39.06%
Formula
Percentage change = [(78 - 128) / 128] x 100
Subtract the new number by the original number
78 - 128 = -50
-50 ÷ 128 = -0.390625
-0.390625 x 100 = -39.06%