I have a Excel file that is imported in from another program as a CSV import.
What I want to do is create a macro that does many different things to
format the sheet to what we need. I can accomplish all, except the following:

I want to be able to have a line at the bottom that has a formula such as

=SUM(First row of data:Last Row of Data)/The number of rows of data

(The total number of rows could be anywhere from 200 to 2000.)

A small sample would be the following:

A B C D
1 Item1 $0.50 EACH 3.0
2 Item2 $1.50 CASE 1.5
3 Item3 $0.75 EACH 4.5
4 Item4 $2.00 EACH 0.75

Average of D: =SUM(D1:D4)/4

Thanks for any help!