-97.81% is the change from 685 to 15
Calculation steps:
[( 15 - 685 ) ÷ 685] x 100 = -97.81%
Formula
Percentage change = [(15 - 685) / 685] x 100
Subtract the new number by the original number
15 - 685 = -670
-670 ÷ 685 = -0.9781021897810219
-0.9781021897810219 x 100 = -97.81%