I need to know if a formula can be constructed that will return the highest
consecutive twelve-month average over a range of months.

Example:
Assume cells A1..A14 represent a single month and contain the following
values.
1, 6, 3, 8, 2, 9, 12, 3, 6, 2, 6, 9, 9, 4

In this example, there are 3 consecutive twelve-month periods, A1..A12,
A2..A13 and A3..A14. The average of A1..A12 = 5.58, A2..A13 = 6.25, and
A3..A14 = 6.08. I want a formula that will return the highest average of the
three, 6.25.

Thanks in advance for any assistance.
-Mark