-18.58% is the change from 786 to 640
Calculation steps:
[( 640 - 786 ) ÷ 786] x 100 = -18.58%
Formula
Percentage change = [(640 - 786) / 786] x 100
Subtract the new number by the original number
640 - 786 = -146
-146 ÷ 786 = -0.18575063613231552
-0.18575063613231552 x 100 = -18.58%