Calculalting Average over period of 2 months

Hi all,

In my cube, i am having the monthly availablity % of an equipment.

In the query i need the number of equipments with availability > x% over the period of two months.

The user will enter the year and the report will display the number of equipments in each month, with the average availability > x% over two months period, ie for February it should display the no. of equipments with average availability > x% in January & February, and so on.

How can I achieve it?

Any help would be appreciated.

Thanks & Regards,

Ankit