Here's the other thread:

http://www.excelforum.com/excel-form...lues-only.html

And here's the array formula** updated for the different ranges:

=AVERAGE(IF(FREQUENCY(IF(B4:B33<>"",MATCH(B4:B33,B4:B33,0)),ROW(B4:B33)-ROW(B4)+1),B4:B33))

** array formulas need to be entered using the key
combination of CTRL,SHIFT,ENTER (not just ENTER).
Hold down both the CTRL key and the SHIFT key
then hit ENTER.