-98.39% is the change from 931 to 15
Calculation steps:
[( 15 - 931 ) ÷ 931] x 100 = -98.39%
Formula
Percentage change = [(15 - 931) / 931] x 100
Subtract the new number by the original number
15 - 931 = -916
-916 ÷ 931 = -0.9838882921589689
-0.9838882921589689 x 100 = -98.39%