-85.07% is the change from 663 to 99
Calculation steps:
[( 99 - 663 ) ÷ 663] x 100 = -85.07%
Formula
Percentage change = [(99 - 663) / 663] x 100
Subtract the new number by the original number
99 - 663 = -564
-564 ÷ 663 = -0.8506787330316742
-0.8506787330316742 x 100 = -85.07%