-20.94% is the change from 807 to 638
Calculation steps:
[( 638 - 807 ) ÷ 807] x 100 = -20.94%
Formula
Percentage change = [(638 - 807) / 807] x 100
Subtract the new number by the original number
638 - 807 = -169
-169 ÷ 807 = -0.2094175960346964
-0.2094175960346964 x 100 = -20.94%