-24.56% is the change from 851 to 642
Calculation steps:
[( 642 - 851 ) ÷ 851] x 100 = -24.56%
Formula
Percentage change = [(642 - 851) / 851] x 100
Subtract the new number by the original number
642 - 851 = -209
-209 ÷ 851 = -0.245593419506463
-0.245593419506463 x 100 = -24.56%