Formula for average of 5 rows

[T15K]

I have the following problem, I would be grateful for any solutions...

In column A, I have about 15000 rows worth of values, and what I need is the average of each 5 rows to appear in column B.

For example;
in cell B1, I need the average of A1-A5
in cell B2, average A6-A10
in cell B3, average of A11-A15
in cell B4, average of A16-20

And so on until each all of column A is averaged (in 5 row blocks) into col B.

I thank you in advance for any assistance provided....

[JBeaucaire]

Put this in B1, then copy down as needed:

=AVERAGE(OFFSET($A$1, (ROW()-1)*5, , 5, ))

[Tony Valko]

Here's another one that doesn't use volatile functions.

=AVERAGE(INDEX(A$1:A$15000,ROWS(B$1:B1)*5-4):INDEX(A$1:A$15000,ROWS(B$1:B1)*5))