Help on expression

[#1]

Here is my requirement,

Fact table contains Week, ID and Status

If there is no data for a week, chart needs to show the previous week's data.

For example,

Week	ID	Status
2012w01	1	Y
2012w01	2	N
2012w01	3	Y
2012w02	1	Y
2012w02	2	Y
2012w04	1	N

Now the below chart needs to be built,

Week	Completed (count of ID with Status 'Y')	NotCompleted (count of ID with Status 'Y')
2012w01	2	1
2012w02	3 (ID-1,2 from the above table, ID-3 is not available in the above table, so it has to consider the status of ID-3 in Week 2012w01)
2012w03	3 (ID 1,2 from 2012w02, ID-3 from 2012w01)
2012w04	2(ID 1,2 from previous weeks)	1

Is it possible to create this chart in UI itself?

Since we dont have ID in the dimension, above function will not work.

Any idea?