-2.38% is the change from 839 to 819
Calculation steps:
[( 819 - 839 ) ÷ 839] x 100 = -2.38%
Formula
Percentage change = [(819 - 839) / 839] x 100
Subtract the new number by the original number
819 - 839 = -20
-20 ÷ 839 = -0.023837902264600714
-0.023837902264600714 x 100 = -2.38%