-17.56% is the change from 991 to 817
Calculation steps:
[( 817 - 991 ) ÷ 991] x 100 = -17.56%
Formula
Percentage change = [(817 - 991) / 991] x 100
Subtract the new number by the original number
817 - 991 = -174
-174 ÷ 991 = -0.17558022199798184
-0.17558022199798184 x 100 = -17.56%