-21.42% is the change from 663 to 521
Calculation steps:
[( 521 - 663 ) ÷ 663] x 100 = -21.42%
Formula
Percentage change = [(521 - 663) / 663] x 100
Subtract the new number by the original number
521 - 663 = -142
-142 ÷ 663 = -0.21417797888386123
-0.21417797888386123 x 100 = -21.42%