-31.31% is the change from 990 to 680
Calculation steps:
[( 680 - 990 ) ÷ 990] x 100 = -31.31%
Formula
Percentage change = [(680 - 990) / 990] x 100
Subtract the new number by the original number
680 - 990 = -310
-310 ÷ 990 = -0.31313131313131315
-0.31313131313131315 x 100 = -31.31%