-19.29% is the change from 793 to 640
Calculation steps:
[( 640 - 793 ) ÷ 793] x 100 = -19.29%
Formula
Percentage change = [(640 - 793) / 793] x 100
Subtract the new number by the original number
640 - 793 = -153
-153 ÷ 793 = -0.19293820933165196
-0.19293820933165196 x 100 = -19.29%