-19.55% is the change from 670 to 539
Calculation steps:
[( 539 - 670 ) ÷ 670] x 100 = -19.55%
Formula
Percentage change = [(539 - 670) / 670] x 100
Subtract the new number by the original number
539 - 670 = -131
-131 ÷ 670 = -0.19552238805970149
-0.19552238805970149 x 100 = -19.55%