-9.09% is the change from 957 to 870
Calculation steps:
[( 870 - 957 ) ÷ 957] x 100 = -9.09%
Formula
Percentage change = [(870 - 957) / 957] x 100
Subtract the new number by the original number
870 - 957 = -87
-87 ÷ 957 = -0.09090909090909091
-0.09090909090909091 x 100 = -9.09%