See any report – data comes first and then the grand total (or other summary calculations). What does the viewer of the report want to look at first? The Grand Total. Should that not be shown in the beginning? Obviously yes.
Resist that urge of putting summary after the data. Put it in the beginning.
Data should be tabular – headings followed by data. Convert it to an Excel table first. Select data – Insert – Table. Now you see Table Tools – Design menu on top. In that give the data a name (default name will be Table1, Table2, etc.). Let us say the name is mydata. Put a few blank rows BEFORE the data and add a formula on top to see the summary. That’s it!