Combined Months of a year into a year

Situation:

I have a worksheet that tracks Propane usage. On one of the columns is the date, I have the '05 and '06 heating seasons, the dates range from 9-2005 to 3-2006 for the '05 season and 9-2006 to 3-2007 for the '06 season.

Goal:

Combine the 9/2005 through 3/2006 dates to read 2005 in a separate column
Combine the 9/2006 through 3/2007 dates to read 2006 in a separate column

Question:

What is the easiest way to perform this function?

See attached file.

Erik