-38.58% is the change from 521 to 320
Calculation steps:
[( 320 - 521 ) ÷ 521] x 100 = -38.58%
Formula
Percentage change = [(320 - 521) / 521] x 100
Subtract the new number by the original number
320 - 521 = -201
-201 ÷ 521 = -0.3857965451055662
-0.3857965451055662 x 100 = -38.58%