-39.91% is the change from 867 to 521
Calculation steps:
[( 521 - 867 ) ÷ 867] x 100 = -39.91%
Formula
Percentage change = [(521 - 867) / 867] x 100
Subtract the new number by the original number
521 - 867 = -346
-346 ÷ 867 = -0.3990772779700115
-0.3990772779700115 x 100 = -39.91%