-20.14% is the change from 839 to 670
Calculation steps:
[( 670 - 839 ) ÷ 839] x 100 = -20.14%
Formula
Percentage change = [(670 - 839) / 839] x 100
Subtract the new number by the original number
670 - 839 = -169
-169 ÷ 839 = -0.20143027413587605
-0.20143027413587605 x 100 = -20.14%