-81.1% is the change from 164 to 31
Calculation steps:
[( 31 - 164 ) ÷ 164] x 100 = -81.1%
Formula
Percentage change = [(31 - 164) / 164] x 100
Subtract the new number by the original number
31 - 164 = -133
-133 ÷ 164 = -0.8109756097560976
-0.8109756097560976 x 100 = -81.1%