Create a Parameter called N and set it to 6.
Create a calculated field which has the following:
if datepart('week',[SOIDATE]) >= datepart('week',today()) - [N] AND
datepart('week',[SOIDATE]) <= datepart('week',today()) then
Replace Amount with your new calculated field in the row shelf.
This calculated field will allow you to see each year dynamically and allow you to drill down your data not only by year. The only caveat is this solution will not show you any information on January 1st because it does not move backwards into the previous year.
That is exactly what I needed. I knew a parameter would help but I couldn't figure out exactly how to get it working correctly. Thanks for the help.