-65.56% is the change from 90 to 31
Calculation steps:
[( 31 - 90 ) ÷ 90] x 100 = -65.56%
Formula
Percentage change = [(31 - 90) / 90] x 100
Subtract the new number by the original number
31 - 90 = -59
-59 ÷ 90 = -0.6555555555555556
-0.6555555555555556 x 100 = -65.56%