Chart item status with "today" in X axis

We use boards to follow item approval processes and we need to know basic information:

  • how many items were approved by week
  • how long it took for an item to be approved and the trend through time (last week it took 3 days, the previous one 5 days, etc)
  • How many items are in a each status today, and how many were in each status last week.

I don’t understand how the X axis date works.