-4.03% is the change from 521 to 500
Calculation steps:
[( 500 - 521 ) ÷ 521] x 100 = -4.03%
Formula
Percentage change = [(500 - 521) / 521] x 100
Subtract the new number by the original number
500 - 521 = -21
-21 ÷ 521 = -0.04030710172744722
-0.04030710172744722 x 100 = -4.03%