Updating

A pivot table is not linked directly to its source data but instead is linked to a special hidden cache of the data.
When a change is made to the data the PivotTable is not updated automatically.
You can refresh the data at any time by clicking on the Refresh Button on the PivotTable toolbar or by using the shortcut menu.
You must refresh the pivot table manually by using the refresh button located both on the PivotTable toolbar and on the shortcut menu.
It is possible to update your pivot table automatically every time the workbook is opened. Select (PivotTable > Table Options) and select "Refresh on Open".
Can you refresh your data at regular intervals, does it refer to Excel data ??