-88.21% is the change from 670 to 79
Calculation steps:
[( 79 - 670 ) ÷ 670] x 100 = -88.21%
Formula
Percentage change = [(79 - 670) / 670] x 100
Subtract the new number by the original number
79 - 670 = -591
-591 ÷ 670 = -0.8820895522388059
-0.8820895522388059 x 100 = -88.21%