If you need a report on Epics by the percentage of stories in progress, follow the steps below:
Open the Time in Status for Jira Cloud app.
2. Filter data by an Epic.
3. Select a Pivot Table view.
4. Then click the Fields option.
5. In the Fields menu, you can customize data presentation by setting your custom fields for Rows, Columns, and Report Filters.
6. Choose a Status from the available fields.
7. Move a status field from the Rows to the Columns.
8. Choose % of rows in the Values.
9. Click the Apply button.