-19.19% is the change from 839 to 678
Calculation steps:
[( 678 - 839 ) ÷ 839] x 100 = -19.19%
Formula
Percentage change = [(678 - 839) / 839] x 100
Subtract the new number by the original number
678 - 839 = -161
-161 ÷ 839 = -0.19189511323003575
-0.19189511323003575 x 100 = -19.19%