Analytics time chart of cumulative curves

Hi everyone, on HealthShare Unified Care Record 2024.1.0 Build, we're using the Analytics section to create a dashboard containing a time chart showing a cumulative curve of the number of documents indexed in the registry for each documentSource of each repository. We tried the following steps: we created a cube whose dimensions are the CreationDate, SourceValue, and repositoryUniqueID of the HS_Registry.Document table; in the Analytics section, we created a pivot table that lists the document creation date on each row, along with as many columns as each repository's documentSources. However, the table displays the number of documents indexed on that specific day, not the cumulative number of documents indexed up to that day. We tried creating a calculated measure in the cube using the MDX sum function and the MDX periodToDate function, but we're unable to achieve the desired result. Can you help us create the right pivot table to obtain the cumulative graph we're interested in? Thanks everyone,
Elisa

Following,
1) a mock graph of the information we would obtain (cumulative curve of the document indexed up to each day per source/repo)

2) the time chart we created in analytics at the moment (number of document per day for each source/repo) and the corresponding pivot table