-89.39% is the change from 660 to 70
Calculation steps:
[( 70 - 660 ) ÷ 660] x 100 = -89.39%
Formula
Percentage change = [(70 - 660) / 660] x 100
Subtract the new number by the original number
70 - 660 = -590
-590 ÷ 660 = -0.8939393939393939
-0.8939393939393939 x 100 = -89.39%