-82.64% is the change from 991 to 172
Calculation steps:
[( 172 - 991 ) ÷ 991] x 100 = -82.64%
Formula
Percentage change = [(172 - 991) / 991] x 100
Subtract the new number by the original number
172 - 991 = -819
-819 ÷ 991 = -0.8264379414732593
-0.8264379414732593 x 100 = -82.64%