What are some good ways to create the table below based on the question?

Below is my attempt to code the table. I don’t know how to achieve the effect of the last row shown above when drawing it. Ideally, the matching types can be automatically entered and the corresponding probability values can be automatically generated.

data = GroupBy[Tuples[{DD, Dd, Dd, dd}, 2], Sort, Length];
events = Subscript[A, #] & /@ Range[6]
keys = Keys[data];
values = Values[data];
Grid[{{"Event", ## & @@ events}, {"Combs", Sequence @@ keys}, {"Ounts",
    Sequence @@ values} , {"P(\!\(\*SubscriptBox[\(A\), \(i\)]\))", 
   Sequence @@ (values/16)}  }, Frame -> All, Alignment -> Center, 
 ItemSize -> {5, Automatic}]