-68.69% is the change from 990 to 310
Calculation steps:
[( 310 - 990 ) ÷ 990] x 100 = -68.69%
Formula
Percentage change = [(310 - 990) / 990] x 100
Subtract the new number by the original number
310 - 990 = -680
-680 ÷ 990 = -0.6868686868686869
-0.6868686868686869 x 100 = -68.69%