-0.4% is the change from 506 to 504
Calculation steps:
[( 504 - 506 ) ÷ 506] x 100 = -0.4%
Formula
Percentage change = [(504 - 506) / 506] x 100
Subtract the new number by the original number
504 - 506 = -2
-2 ÷ 506 = -0.003952569169960474
-0.003952569169960474 x 100 = -0.4%