-74.07% is the change from 991 to 257
Calculation steps:
[( 257 - 991 ) ÷ 991] x 100 = -74.07%
Formula
Percentage change = [(257 - 991) / 991] x 100
Subtract the new number by the original number
257 - 991 = -734
-734 ÷ 991 = -0.7406659939455096
-0.7406659939455096 x 100 = -74.07%