Martix run-off calculation

[dtalb]

Hi

I have a matrix/pivot table visual like this:

Date Row = is the cohort ie sales date

Date Column = is the transaction date

I need to work out the percentage relative to the first value in the row (ie the diagonal):

How do I create a measure that returns the value in the diagonal in all the columns:

Thanks

[dtalb]

Example pbx: https://we.tl/t-ldTXNDo3gk

[lbendlin]

Please provide sanitized sample data that fully covers your issue.
https://community.powerbi.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-Forum/ba-...
Please show the expected outcome based on the sample data you provided.

https://community.powerbi.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447523