The dates I've seen would tend to indicate they were mostly 12 or 6 month intervals, depending on the year between 2001 and 2006 but I've only seen one card dated in 2006 and none in 2005.

There were Silver and Platinum Club cards issued later in 2007 (8th issue) but I've only seen 06/30/07 expiration dates on those

Here's what I have discovered so far for the Gold Club cards....

Gold (Gold Club – Expires 03/31/01)

Gold (Gold Club – Expires 03/31/02)

Gold (Gold Club – Expires 09/30/02)

Gold (Gold Club – Expires 03/31/03)

Gold (Gold Club – Expires 09/30/03)

Gold (Gold Club – Expires 03/31/04)

Gold (Gold Club – Expires 9/30/04)

White/Gold (Gold Club – Expires 12/31/02)

White/Gold (Gold Club – Expires 06/30/03)

White/Gold (Gold Club – Expires 9/30/06)

If you have any other dates, please send me scans so we can get them added.