-21.5% is the change from 521 to 409
Calculation steps:
[( 409 - 521 ) ÷ 521] x 100 = -21.5%
Formula
Percentage change = [(409 - 521) / 521] x 100
Subtract the new number by the original number
409 - 521 = -112
-112 ÷ 521 = -0.21497120921305182
-0.21497120921305182 x 100 = -21.5%