Sum the XX best values

[#1]

Hi all,

I'm seeking for a solution to sum the xx best values from my field.

If I have 9, 8, 7, 6, 5, 4, 3, 2, 1 and i want the sum of the 5 best values, it will be 9+8+7+6+5 = 35

The difficulty is that if I have 9, 8, 8, 7, 6, 5, 4, 3, 2, 1 and i always want the sum of the 5 best values, it will be 9+8+8+7+6 = 38

Many thanks for the person who will help me ! [;)]