-74.48% is the change from 670 to 171
Calculation steps:
[( 171 - 670 ) ÷ 670] x 100 = -74.48%
Formula
Percentage change = [(171 - 670) / 670] x 100
Subtract the new number by the original number
171 - 670 = -499
-499 ÷ 670 = -0.744776119402985
-0.744776119402985 x 100 = -74.48%