-8.42% is the change from 950 to 870
Calculation steps:
[( 870 - 950 ) ÷ 950] x 100 = -8.42%
Formula
Percentage change = [(870 - 950) / 950] x 100
Subtract the new number by the original number
870 - 950 = -80
-80 ÷ 950 = -0.08421052631578947
-0.08421052631578947 x 100 = -8.42%