-49.8% is the change from 990 to 497
Calculation steps:
[( 497 - 990 ) ÷ 990] x 100 = -49.8%
Formula
Percentage change = [(497 - 990) / 990] x 100
Subtract the new number by the original number
497 - 990 = -493
-493 ÷ 990 = -0.49797979797979797
-0.49797979797979797 x 100 = -49.8%