-21.57% is the change from 663 to 520
Calculation steps:
[( 520 - 663 ) ÷ 663] x 100 = -21.57%
Formula
Percentage change = [(520 - 663) / 663] x 100
Subtract the new number by the original number
520 - 663 = -143
-143 ÷ 663 = -0.21568627450980393
-0.21568627450980393 x 100 = -21.57%