-6.21% is the change from 870 to 816
Calculation steps:
[( 816 - 870 ) ÷ 870] x 100 = -6.21%
Formula
Percentage change = [(816 - 870) / 870] x 100
Subtract the new number by the original number
816 - 870 = -54
-54 ÷ 870 = -0.06206896551724138
-0.06206896551724138 x 100 = -6.21%