-97.9% is the change from 715 to 15
Calculation steps:
[( 15 - 715 ) ÷ 715] x 100 = -97.9%
Formula
Percentage change = [(15 - 715) / 715] x 100
Subtract the new number by the original number
15 - 715 = -700
-700 ÷ 715 = -0.9790209790209791
-0.9790209790209791 x 100 = -97.9%