Hoping someone can help me, as I cant get my head around how to work out what the average rating of a team score would be, based on a formula!

I have four teams, with scores rated from Excellent to Poor. How would I create a formula to show what the average score is? I have attached a screenshot below for clarity. So for eg, if a team has 50% in Excellent, and 50% in poor, it would return ‘Good’ as the average. Whereas if another team could have 25% in Good, and 75% in poor, so it would return Poor as the average team rating.

Thank you in advance for your help!