Statistics: a "date" Dynamic Field not displaying

[McbrR]

Hello,

I have created a "date" dynamic field in the "New phone ticket" form.
Agents toogle it on then select the appropriate date and click "Create".

I would like to include it in my statistics, but it is not displaying in the list when editing or creating a statistic (Step 2).

Do you know why this may be?

McbrR