Matrix with dynamic columns of the last 3 years

[nimp_kp]

Hi

I'm trying to create a matrix table that shows the sales at two specific dates each year for the last 3 years.

The specific dates are february 1st and july 1st.

As of today, the table should have 7 date columns: july 1st 2016, february 1st 2017....july 1st 2019. 

I want the table to show every sales date in between the newest sales date and 3 years back. As of today that is july 1st 2016 to july 1st 2019.

When we get to february 1st 2020 the measure should dynamically change the columns so the newest sales date is february 1st 2020 and the oldest is february 1st 2017.

Something like this:

What the table should show today:

	20160701	20170201	20170701	20180201	20180701	20190201	20190701
sales	1000	1000	2000	2000	1000	1500	1200

What the table should show when we reach february 1st 2020:

	20170201	20170701	20180201	20180701	20190201	20190701	20200201
sales	1000	2000	2000	1000	1500	1200	2000

Thanks