-40.92% is the change from 391 to 231
Calculation steps:
[( 231 - 391 ) ÷ 391] x 100 = -40.92%
Formula
Percentage change = [(231 - 391) / 391] x 100
Subtract the new number by the original number
231 - 391 = -160
-160 ÷ 391 = -0.4092071611253197
-0.4092071611253197 x 100 = -40.92%