You can "make" it yourself, but it should be an available column on the Stats tab as well as an available variable on the overall scores formula. I'll add them.

In the meantime, you can compute the average rank by using the Tournament Scores formula along with the Overall Scores formula. Set the Tournament Scores formula to:

`rank`

And set the Overall Scores formula to:

`average(scores)`

It will then show up in the Overall Scores column.