End Date Use this field to specify the end date at which to stop computing time trends. The date must be in ISO-8601 format. For example, September 1, 2011 must be entered as 2011-9-01 . If you leave this field blank, the latest value of RFENDTC from DM or ADSL is used. This field is available only when the Compute Time Trends check box has been checked. To Specify a Start Date: Check the Compute Time Trends check box. Left-click in the field and enter the end date (in ISO-8601 format) in the field, as shown below: