-83.55% is the change from 991 to 163
Calculation steps:
[( 163 - 991 ) ÷ 991] x 100 = -83.55%
Formula
Percentage change = [(163 - 991) / 991] x 100
Subtract the new number by the original number
163 - 991 = -828
-828 ÷ 991 = -0.8355196770938446
-0.8355196770938446 x 100 = -83.55%