-23.12% is the change from 839 to 645
Calculation steps:
[( 645 - 839 ) ÷ 839] x 100 = -23.12%
Formula
Percentage change = [(645 - 839) / 839] x 100
Subtract the new number by the original number
645 - 839 = -194
-194 ÷ 839 = -0.23122765196662692
-0.23122765196662692 x 100 = -23.12%