Last 6 months of data from current date

Hi Experts,

I have a requirement in WebI to display last 6 months of data based on current date.Actually I have a column called "Employee Contract Start date" in my report.Suppose the end user executes the report today,then he should be able to see the Employee's data whose contract started today and in the last 6months from current date.
Also I have dimension object name "Employee Contract Start Date".

Please be noted that I am getting the data from Bex Query and I am working on BO 4.1 version.

I have Objects "Calender day" , "Cal.year/Month" , "Calender month" , "Employee Contract Start Date" in the BEx Query.

Could anyone please propose me, what are the ways to meet this requirement?