-68.69% is the change from 99 to 31
Calculation steps:
[( 31 - 99 ) ÷ 99] x 100 = -68.69%
Formula
Percentage change = [(31 - 99) / 99] x 100
Subtract the new number by the original number
31 - 99 = -68
-68 ÷ 99 = -0.6868686868686869
-0.6868686868686869 x 100 = -68.69%