Bar chart

[qvqfqlik]

Need some help with showing burn down in bar chart or waterfall chart.

I tried to do below, but the result is not correct.

Dimension:

=Pick(DIM, TPN, 'Total')

Measure: Count(distinct total WorkItem_ID) - RangeSum(Above(Count(distinct WorkItem_ID),1,rowno()))

Below is the barchart for which Iam trying to do burndown.

Below is the burndown chart result that Iam getting (not correct).

Below is the expected burndown chart.