Expression: Count of Y where X = Mode(X)

[felix18807]

I'm looking to do a count of a field where another value field is the mode of that value field -  (Count of Y where X = Mode(X))

The problem if futher complicated where there is more than one modal value (the mode function appears to produce nulls for these values).

I'm attempting this in a pivot table and I need to be able to see this value in order to make a judgement on the most relevant value for each row.

Has anyone been able to do anything like this?