-0.19% is the change from 521 to 520
Calculation steps:
[( 520 - 521 ) ÷ 521] x 100 = -0.19%
Formula
Percentage change = [(520 - 521) / 521] x 100
Subtract the new number by the original number
520 - 521 = -1
-1 ÷ 521 = -0.0019193857965451055
-0.0019193857965451055 x 100 = -0.19%