-40.33% is the change from 538 to 321
Calculation steps:
[( 321 - 538 ) ÷ 538] x 100 = -40.33%
Formula
Percentage change = [(321 - 538) / 538] x 100
Subtract the new number by the original number
321 - 538 = -217
-217 ÷ 538 = -0.4033457249070632
-0.4033457249070632 x 100 = -40.33%