-35.32% is the change from 991 to 641
Calculation steps:
[( 641 - 991 ) ÷ 991] x 100 = -35.32%
Formula
Percentage change = [(641 - 991) / 991] x 100
Subtract the new number by the original number
641 - 991 = -350
-350 ÷ 991 = -0.35317860746720486
-0.35317860746720486 x 100 = -35.32%