-7.1% is the change from 915 to 850
Calculation steps:
[( 850 - 915 ) ÷ 915] x 100 = -7.1%
Formula
Percentage change = [(850 - 915) / 915] x 100
Subtract the new number by the original number
850 - 915 = -65
-65 ÷ 915 = -0.07103825136612021
-0.07103825136612021 x 100 = -7.1%