-81.31% is the change from 915 to 171
Calculation steps:
[( 171 - 915 ) ÷ 915] x 100 = -81.31%
Formula
Percentage change = [(171 - 915) / 915] x 100
Subtract the new number by the original number
171 - 915 = -744
-744 ÷ 915 = -0.8131147540983606
-0.8131147540983606 x 100 = -81.31%