**What I have? **I am having a very large table of data containing cricket information.

**What I want? **I am trying to calculate the **average number of runs per match** for Australia (and other countries) in years 2013, 2014, and 2015.

**What I got? **I was able to calculate the average runs per year into a graph and currently I have a bar chart that somewhat looks like this:

year 2013 | 2014 | 2015
total runs 1037 | 1835 | 177

But I want the one that divides that total by the number of matches per year (6, 13, and 1 respectively) and looks like this:

year 2013 | 2014 | 2015
avg runs per match 173 | 141 | 177

but I don't know how to conduct a calculation on these numbers to divide that total over the number of games played. There is a column in my set called 'MID' for Match ID. Obviously, summing the number of MID for 2013 would give me the needed number, 6.

Ideally, I would divide the total number of runs by the number of unique items in the MID column, but I do not know how to do this. If this makes any sense at all, would anyone have a simple way of doing this? Thanks in advance.