-40.45% is the change from 539 to 321
Calculation steps:
[( 321 - 539 ) ÷ 539] x 100 = -40.45%
Formula
Percentage change = [(321 - 539) / 539] x 100
Subtract the new number by the original number
321 - 539 = -218
-218 ÷ 539 = -0.4044526901669759
-0.4044526901669759 x 100 = -40.45%