-89.1% is the change from 670 to 73
Calculation steps:
[( 73 - 670 ) ÷ 670] x 100 = -89.1%
Formula
Percentage change = [(73 - 670) / 670] x 100
Subtract the new number by the original number
73 - 670 = -597
-597 ÷ 670 = -0.891044776119403
-0.891044776119403 x 100 = -89.1%