-2.26% is the change from 839 to 820
Calculation steps:
[( 820 - 839 ) ÷ 839] x 100 = -2.26%
Formula
Percentage change = [(820 - 839) / 839] x 100
Subtract the new number by the original number
820 - 839 = -19
-19 ÷ 839 = -0.02264600715137068
-0.02264600715137068 x 100 = -2.26%