-20.45% is the change from 807 to 642
Calculation steps:
[( 642 - 807 ) ÷ 807] x 100 = -20.45%
Formula
Percentage change = [(642 - 807) / 807] x 100
Subtract the new number by the original number
642 - 807 = -165
-165 ÷ 807 = -0.20446096654275092
-0.20446096654275092 x 100 = -20.45%