Assuming that your numbers are from A2 to F2, here is a very simpl

solution, i.e., not an elegant formula but will work.

If you want the percentages to appear below the numbers, enter in B2

=if(A2="","",A2/sum($A$2+$F$2))

and copy this up to cell F2.

Another option is

=if(A2="",0,A2/sum($A$2:$F$2))

Also, don't forget to "percent" format your cells (B2:F2).