Average Review Rating shows how the value of Views

I have managed to set up the NodeReview module system of 5 axis. I was able to configure Views to display the average of votes on a view page.

See screenshot:

But now I'm faced with the new challenge: to display the average of overall votes (by summing up all 5 axis, then average.)

For example, given a voting scores like below:

First axis: Yönetim - 70%
Second axis: Senaryo - 85%
Third axis: Oyunculuk - 90%
Fourth axis: Görüntü - 60%
Fifth axis: Müzik - 60%

Therefore the average of the above = (70+85+90+60+60)/5 = 73%

what I need now is to add a column to the views page and display the average. What should I do to achieve that?

Could you please help me urgently?

thanks in advance.