To do this you will have to pivot your data source. Go to data source and control and click on the two date fields:
Then right click and pivot. Automatically Tableau will create two new fields called pivot field names and pivot field values.
Create your view by doing this bringing the pivot field names into rows, then ID next to it:
Then you can drag total members into text, then go to the analytics pane and select totals and drag it into the view to get the grand total:
Thanks Mavis for replying to my question however my actually data is a sas data set and its not allowing pivot. so it there another way to do this without the pivot.