-87.61% is the change from 670 to 83
Calculation steps:
[( 83 - 670 ) ÷ 670] x 100 = -87.61%
Formula
Percentage change = [(83 - 670) / 670] x 100
Subtract the new number by the original number
83 - 670 = -587
-587 ÷ 670 = -0.8761194029850746
-0.8761194029850746 x 100 = -87.61%