-39.57% is the change from 839 to 507
Calculation steps:
[( 507 - 839 ) ÷ 839] x 100 = -39.57%
Formula
Percentage change = [(507 - 839) / 839] x 100
Subtract the new number by the original number
507 - 839 = -332
-332 ÷ 839 = -0.3957091775923719
-0.3957091775923719 x 100 = -39.57%