Excel Graph Auto-Adaptative

I have a problem. I have a graph with 2 columns.

One is the dates, the other is figures.

12/12    100
13/12    150
14/12    180

Actually inside each cells there is a formula =if(Sheet1!A1= "","", B1*C1) etc... so my 2 columns got only 3 "filled" with numbers rows, but there is actually formula for around 20 rows.

Now I am trying to do an auto-adaptive graph. I just want the graph to take the now dates and numbers.

The problem is, with regualar way to do it with name manager OFFSET ((=OFFSET('Sheet2'!$F$9,0,0,COUNTA('Sheet2'!$F:$F)) , it will also take the blank cells where there is formulas inside too...

How to do?

Thanks