There may be a few ways to approach this.
The feasibility of the solution will depend on your datasource type
and on the size of your dataset.
One method is described here:
It has been employed on your data in the workbook attached in the Forum Thread.
I may have mis-interpreted, but I made the assumption that the Open status meant
the first time the model was Open was on that ModDate. Then using Level of Detail
calculations, I fixed the Open and Close ModDates to every row for that Model.
I then joined the data to a lookup table which is simply a column of all months from 1/12004
to 12/2018. The join was on a calculated field of 1.
Off the bat, these two steps (LODs and cross join on 1) may cause performance issues if your dataset is large.
But there will be a filter step to include only those lookup dates that are in between the Open and Close dates.
Once that is all done, a CountD of Model vs. Lookup Month can be plotted.
Another method is described here:
Though the data table layout looks different from yours, it may still work the Level of Detail fields described above.
That's really great and it is EXACTLY what I was looking for.
Glad that worked for you,
All the best.