Mean of array

[Monti]

Hi all,
i am new here and hope i can find some help.

i have a two dimensional array. in the first column is the distance in mm and in the second column are height values.
i want to calculate the mean of the z values every centimeter. the amount of values per centimeter is not constant.
i dont have a clue how to do this.
i hope you can help me
Thanks
Monti