-8.7% is the change from 115 to 105
Calculation steps:
[( 105 - 115 ) ÷ 115] x 100 = -8.7%
Formula
Percentage change = [(105 - 115) / 115] x 100
Subtract the new number by the original number
105 - 115 = -10
-10 ÷ 115 = -0.08695652173913043
-0.08695652173913043 x 100 = -8.7%