Specify Subtotals (New Layout/Report assistant)
If you selected Include Subtotals in the Include Subtotals and Grand Totals panel, you can use this panel to define how they appear.
Note  FileMaker Pro uses the term subsummary to include not only subtotals, but also averages, counts, and other summary data for a subset of records (the categories of records you defined in the Organize Records by Category panel).
To specify a subtotal:
1. For Summary field, click Specify.
The Specify Field dialog box appears.
2. Choose a summary field from the list, or define a new summary field. (Only fields defined as the summary field type are available in the list.)
To define a summary field in the current table, click Add. See Options for Summary Field dialog box (New Layout/Report assistant).
To define a summary field in another table, choose Manage Database from the list. See Defining summary fields.
Note  You must have full access privileges to define summary fields.
3. Click OK.
4. For Category to summarize by, choose a break field.
For example, if you are subtotaling sales data by region, choose the Region field. The fields that appear in this list are the ones that you selected in the Organize Records by Category panel.
5. For Subtotal placement, choose Above record group, Below record group, or Above and below.
FileMaker Pro places the summary field vertically in line with the field the summary field is based on.
6. Click Add Subtotal.
7. Repeat the above steps for each subtotal (subsummary) that you want to add.
Notes and tips
To remove a subsummary, select the subsummary definition in Subtotals, then click Remove Subtotal or double-click the subsummary in the list.
To change a subsummary, remove the subsummary definition and redefine it.
When you define a subsummary in this panel, you are defining a leading subsummary part. If, for Subtotal placement, you choose Above record group or Above and below, you’re also defining a trailing subsummary part. After you finish with the assistant, you can modify characteristics like pagination and page numbering. See Changing a layout part.
If, for Subtotal placement, you choose Below record group, FileMaker Pro not only creates a trailing subsummary part to hold the break field and the summary field you specify, but also creates a leading subsummary part containing only the break field.
If you define more than one subsummary for the same break field with the same placement, the order in which you define the subsummary fields in the assistant the order of the summary fields in the subsummary part in the report. You can change the order of the summary fields after you finish the assistant.
Related topics 
Creating a layout