Need to sort range of values so it only selects one date to the range

Hi in need of same desperate help, have spent the last 4 to five hours trying to find a solution and hoping someone out there can make some magic for me.

as per attached spreedsheet to reference to.

Sheet 1 (2) is my data range in column A are a list of the POs i have outstanding, as you can see the same number appears more than once. In column J is the required delivery date.

Sheet Graph - i have created a graph to capture the % that are outstanding by how many days, however it captures multiple lines for the same PO# mutliple times when the delivery date in column j is the same, it only needs to capture the number once. It is distorting the actual figures.

Sheet Graph Data - is how im going about getting the data to the graph, basically i need to know how i can get it to only count one of the multiple PO# in sheet 1 (2) and the due date instead at the moment it counts the same po # multiple times instead of just once. As you can see in sheet 1 (2) column T i only have 141 purchase orders in total, so the graph needs to show the same and the depending on the due date for the 141 po's

note - Sheet 1(2) is constantly changing from day to day in regards to the POnum etc etc and it is imported from maximo so cant chnge much on sheet1(2)

i hope someone can help me with this it would be greatly appreciated