Hello Mr. Lodhi,
I have reviewed your data set and i found that using "State Incident as In progess, New and On-hold" there are 38 rows are coming.
Header Created you have used for taking as backlog date. This header contains only data for Mar, April and May'2017.
So, if i select in data file, March there is 1 backlog, 1 for April and 36 for May. If this is the correct backlog. Please refer the attached workbook. In case of any question, just let me know.
In case you want only the previous data of backlog month just update the backlog calculated field as (DATEDIFF('month', [Backlog Month],[Created]))<0.
Backlog_Count.twbx 2.5 MB
You resolved my issue.
Issue got resolved...thanks for reply.
glad to happy and happy it works for you