-49.85% is the change from 991 to 497
Calculation steps:
[( 497 - 991 ) ÷ 991] x 100 = -49.85%
Formula
Percentage change = [(497 - 991) / 991] x 100
Subtract the new number by the original number
497 - 991 = -494
-494 ÷ 991 = -0.49848637739656915
-0.49848637739656915 x 100 = -49.85%