I have a data set that looks like this:

From_Network, From_Node, To_Node, To_Network, Count
4,304,2,350,14000
4,304,2,650,4001
4,304,5,150,3005
4,304,2,250,240
4,304,2,250,50
4,310,2,350,16000
4,310,2,650,12000
4,310,5,150,1000
4,310,2,250,100

How can I get the average number of "Count"s for each of 1st highest count until and N+ highest. I.E. the for the first hightest count the average would be (14000/16000)/2 = 15000

So my dataset when I query would look like:

15000
8000.5
2002.5
170
25

I have no idea on how to start this. How would this work?