-68.62% is the change from 991 to 311
Calculation steps:
[( 311 - 991 ) ÷ 991] x 100 = -68.62%
Formula
Percentage change = [(311 - 991) / 991] x 100
Subtract the new number by the original number
311 - 991 = -680
-680 ÷ 991 = -0.686175580221998
-0.686175580221998 x 100 = -68.62%