Good afternoon,
I have a set of data that in order to mitigate seasonality in the figures from one month to another i would like to compare Last 12 Months period to Last 12 Months -1 and so on in for each month.
The data i have is monthly and would need to aggregate/group each month into buckets of 12. Example of how would be the mapping:

The mapping is too big and would need to be maintained each month and i am trying to built a more elegant solution.
I am thinking in assigning a number to each month + year and then using a formula aggregate the multiple month into categories. The challenge i find is easily aggregate the same month in different categories without entering in a manual selection.
I attach example datasource. The real has 27 months and a lot of granularity.
Final result would look like Last 12 Month as columns and sales as rows:

Thanks! Feel free to share ideas, i can give them a try.
kind regards,
Kylian