-31.17% is the change from 231 to 159
Calculation steps:
[( 159 - 231 ) ÷ 231] x 100 = -31.17%
Formula
Percentage change = [(159 - 231) / 231] x 100
Subtract the new number by the original number
159 - 231 = -72
-72 ÷ 231 = -0.3116883116883117
-0.3116883116883117 x 100 = -31.17%