-80.5% is the change from 159 to 31
Calculation steps:
[( 31 - 159 ) ÷ 159] x 100 = -80.5%
Formula
Percentage change = [(31 - 159) / 159] x 100
Subtract the new number by the original number
31 - 159 = -128
-128 ÷ 159 = -0.8050314465408805
-0.8050314465408805 x 100 = -80.5%