-9.38% is the change from 960 to 870
Calculation steps:
[( 870 - 960 ) ÷ 960] x 100 = -9.38%
Formula
Percentage change = [(870 - 960) / 960] x 100
Subtract the new number by the original number
870 - 960 = -90
-90 ÷ 960 = -0.09375
-0.09375 x 100 = -9.38%