sharepoint average list

Perhaps someone can assist me with the following how to get the average score in this taxonomy list

I have a sharepoint list as follows

Taxonomy Name     Score     Average Score

Taxonomy1           4             3.67

Taxonomy1           4             3.67

Taxonomy1           3             3.67

Taxonomy2          9              5

Taxonomy2          1              5

Hope someone can help me out

Rgds

Arthur