Historical Count based on status in a workflow

Hi there,

I'm pulling data from jira for a Support Desk. I monitor live status (i.e. how many tickets are in each status of the workflow RIGHT NOW) and that works fine - but i want to create a historical view of the data to measure, for example, how many tickets have been in the backlog over time. i.e. if i currently have 20  tickets in the backlog - is that a historically high or low number. The ideal output would be a line/bar chart by day.

The data-set records the date a ticket moves to each status and i have included a sample of below. I am really struggling to work out how to write measures to get this number. My theory was that i needed to write something that counts the number of tickets whose most recent update is before or on ( <= ) [date on graph] and status is 'backlog' .

Although ive tried many mixtures of calculates, lastdates in both measures and calculated columns attached to calendar tables im drawing a complete blank. Is there anyone who can assist?

Sample data: