-20.75% is the change from 670 to 531
Calculation steps:
[( 531 - 670 ) ÷ 670] x 100 = -20.75%
Formula
Percentage change = [(531 - 670) / 670] x 100
Subtract the new number by the original number
531 - 670 = -139
-139 ÷ 670 = -0.20746268656716418
-0.20746268656716418 x 100 = -20.75%