-33.03% is the change from 990 to 663
Calculation steps:
[( 663 - 990 ) ÷ 990] x 100 = -33.03%
Formula
Percentage change = [(663 - 990) / 990] x 100
Subtract the new number by the original number
663 - 990 = -327
-327 ÷ 990 = -0.3303030303030303
-0.3303030303030303 x 100 = -33.03%