Refreshing Dates in a Pivot Table

Hello-

I have a set of pivot tables that each have 3 columns of 24 values:

1) Hour
2) Hourly Data from a particular date
3) Hourly Data from 7 days prior to the particular date in (2)


Currently, I click through the pivot table options to get (2) and (3) set to the correct days.

What is the most efficient way to have the pivot table update so that (2) applies to today's date and (3) applies to 7 days prior to today's date? (I have many of these tables, and I update ever day, so I am trying to create an automated solution).

Thanks!
Utter