How do i get POWERPIVOT data for the same days last year?

[shophoney]

Hi I'm look to get the MTD sales for the same days last year.

IE May 1-8 of 2016 vs. May 1-8 2017.

Or in a perfect world May2-9, 2016 vs. May 1-8, 2017

This gives me all of May last year:
1 YR AGO SALES NET RETAIL:=CALCULATE('tblInvSkuMaster'[SALES TOTAL NET RETAIL],dateadd(dCalendar[DATES],-364,DAY))


​Thanks