Average only for specific pairs of cells

[DaanN]

Hi all!

I have bi-annual data in a row and i want an annual average. How can I get the average for each year next to each other?

e.g. imagine a , is for a new cell, i would want this

SEMI ANNUAL DATA: 2,4,6,8,6,4,2,8
ANNUAL AVG: 3,7,5,5

So I hope it is clear that I want to skip some cells so that I do not get the average of e.g. second half of 2011 and the first half of 2012. I only want the averages of each year: so average of first half of 2011 and second half of 2011.
I hope its clear.

Daan

 

[DaanN]

I doubt whether I was clear let me add:
data is in: a1, b1 ,c1, d1, e1, f1 etc
output that i want: average(a1,b1),average(c1,d1),average(e1,f1) etc