[AccessD] Two counts, one unique in pivot table

Hi all,

I'm trying to produce a pivot table in Access that has two counts in it.

One of these is based upon a field that is unique within the data and 
another that can have duplicates.

What I need to show is, based upon the small example, this

SAMPLE NUMBER        PATIENT NUMBER
A.1                                                1
A.2                                                2
A.3                                                2
A.4                                                2
A.5                                                3
A.6                                                4
A.7                                                4
A.8                                                5
A.9                                                5
A.10                                              6

10                                                  6

which would show that there were 10 visits made by 6 distinct patients.

Could anyone point me in the right direction as to how to achieve this ?

Many thanks in advance,

Chris Swann