-9.79% is the change from 715 to 645
Calculation steps:
[( 645 - 715 ) ÷ 715] x 100 = -9.79%
Formula
Percentage change = [(645 - 715) / 715] x 100
Subtract the new number by the original number
645 - 715 = -70
-70 ÷ 715 = -0.0979020979020979
-0.0979020979020979 x 100 = -9.79%