-87.46% is the change from 670 to 84
Calculation steps:
[( 84 - 670 ) ÷ 670] x 100 = -87.46%
Formula
Percentage change = [(84 - 670) / 670] x 100
Subtract the new number by the original number
84 - 670 = -586
-586 ÷ 670 = -0.8746268656716418
-0.8746268656716418 x 100 = -87.46%