-50.05% is the change from 991 to 495
Calculation steps:
[( 495 - 991 ) ÷ 991] x 100 = -50.05%
Formula
Percentage change = [(495 - 991) / 991] x 100
Subtract the new number by the original number
495 - 991 = -496
-496 ÷ 991 = -0.5005045408678103
-0.5005045408678103 x 100 = -50.05%