Creating report based on when jobs were still open

Hi,

I have some data in the following format:

I want to get a summary table, about for each month, how many jobs I had open. So for the above data it would be:

I can do the raised and closed, but am struggling with the open. I tried using a testfilter, with a lot of if statements, which works, but then I not sure how to export that into a format that i can use the data.

Help :)