-17.68% is the change from 990 to 815
Calculation steps:
[( 815 - 990 ) ÷ 990] x 100 = -17.68%
Formula
Percentage change = [(815 - 990) / 990] x 100
Subtract the new number by the original number
815 - 990 = -175
-175 ÷ 990 = -0.17676767676767677
-0.17676767676767677 x 100 = -17.68%