-50.25% is the change from 999 to 497
Calculation steps:
[( 497 - 999 ) ÷ 999] x 100 = -50.25%
Formula
Percentage change = [(497 - 999) / 999] x 100
Subtract the new number by the original number
497 - 999 = -502
-502 ÷ 999 = -0.5025025025025025
-0.5025025025025025 x 100 = -50.25%