-1.31% is the change from 840 to 829
Calculation steps:
[( 829 - 840 ) ÷ 840] x 100 = -1.31%
Formula
Percentage change = [(829 - 840) / 840] x 100
Subtract the new number by the original number
829 - 840 = -11
-11 ÷ 840 = -0.013095238095238096
-0.013095238095238096 x 100 = -1.31%