-21.65% is the change from 231 to 181
Calculation steps:
[( 181 - 231 ) ÷ 231] x 100 = -21.65%
Formula
Percentage change = [(181 - 231) / 231] x 100
Subtract the new number by the original number
181 - 231 = -50
-50 ÷ 231 = -0.21645021645021645
-0.21645021645021645 x 100 = -21.65%