-49.45% is the change from 999 to 505
Calculation steps:
[( 505 - 999 ) ÷ 999] x 100 = -49.45%
Formula
Percentage change = [(505 - 999) / 999] x 100
Subtract the new number by the original number
505 - 999 = -494
-494 ÷ 999 = -0.4944944944944945
-0.4944944944944945 x 100 = -49.45%