-84.38% is the change from 128 to 20
Calculation steps:
[( 20 - 128 ) ÷ 128] x 100 = -84.38%
Formula
Percentage change = [(20 - 128) / 128] x 100
Subtract the new number by the original number
20 - 128 = -108
-108 ÷ 128 = -0.84375
-0.84375 x 100 = -84.38%