Expiration Date

After being married for over eight years, I just found this out the other day. When Paul is buying something with a credit card, and it asks for the date of expiration, and say, the card says "10/31/09", he doesn't say "10-09", but "11-09" since that's the day it has actually expired.

Who does that?

Do you?

Am I the only one who says "10-09"?

Interestingly, the payment is accepted both ways.