-80% is the change from 135 to 27
Calculation steps:
[( 27 - 135 ) ÷ 135] x 100 = -80%
Formula
Percentage change = [(27 - 135) / 135] x 100
Subtract the new number by the original number
27 - 135 = -108
-108 ÷ 135 = -0.8
-0.8 x 100 = -80%
Example