RangeSum Table value as KPI

[RRamos]

Hi all,

I have a table which shows the sum of the last 7 rows (see attached) . 

The table expression I'm using is:

RangeSum(Above( (Count( distinct ItemID)) , 0, 7))

I want to have the sum of the last 7 rows as a KPI chart but I'm finding it difficult to achieve this. 

Has anyone had this issue before and know how to make it work?

Many thanks all