-5.4% is the change from 870 to 823
Calculation steps:
[( 823 - 870 ) ÷ 870] x 100 = -5.4%
Formula
Percentage change = [(823 - 870) / 870] x 100
Subtract the new number by the original number
823 - 870 = -47
-47 ÷ 870 = -0.054022988505747126
-0.054022988505747126 x 100 = -5.4%