-8.15% is the change from 871 to 800
Calculation steps:
[( 800 - 871 ) ÷ 871] x 100 = -8.15%
Formula
Percentage change = [(800 - 871) / 871] x 100
Subtract the new number by the original number
800 - 871 = -71
-71 ÷ 871 = -0.08151549942594719
-0.08151549942594719 x 100 = -8.15%