Creating a Group Footer that Includes an Aggregate Function
To add a group footer:
1. Select Group Header/Footer in the Insert menu.
2. Click the Field () button on the formatting toolbar and drag a field to the Group Footer section.
3. Set the DataField property that you want to calculate in the field.
4. Select a function from the SummaryFunc property list box.
5. Select a group header from the SummaryGroup property list box.
6. Select the summary type from the SummaryType property list box.
7. Add a label to the group footer. See Changing the Labels in a Page Header.