Thought you wanted all the results neatly bunched at the top, w/o any gaps ?
<g>
The earlier suggestion would do just that
Anyway, if you really want the results listed in the manner as per your
response below, where the values to be averaged are running in B1 down
Put in C1:
=IF(MOD(ROWS($1:1)-1,15)=14,AVERAGE(OFFSET(B1,,,-15)),"")
Copy C1 down as far as required. This will return the results exactly as
indicated in your response.

Signature
Max
Singapore
http://savefile.com/projects/236895
xdemechanik
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> Hi Max
>
[quoted text clipped - 35 lines]
> 20/08/2007 19:50 0.8360
> 20/08/2007 19:51 0.7940 0.8434