Rolling Chart with Repeating Dates

[rj2]

I am trying to create a rolling chart that graphs data from the past 12 months. Graphing only a certain number of points will not work because some months there is no data and some months there are multiple data points. If data was taken from the same date it should appear on the same x coordinate. Currently, the same dates are repeating on the x-axis like this:

Is there a set of formulas that allow for what I am describing?

 

[rekakoma]

Calculation =Calculate(Sum([Sales]),Filter(Range,Range[Date]<=EOMONTH(TODAY(),-13) && Range[Date]>=EOMONTH(TODAY(),-25)+1))
But I don't know exactly. If you want complete knowledge take online training, here is the source: Excel Training, they are providing blogs for excel also.