My Xbox Year Number (Next to Gamertag)

It isn't the amount of time you've had Xbox Live account.  It's the amount of time you've had a GOLD subscription.  So any time you have had a silver account, that time will be paused until you go gold again.  Once you go back to gold, the time resumes.  Here's an example:
 

• You start a gold account with a 3 month card on 18th January 2010
• On the 18th April 2010 you can't afford to renew the account, so it turns silver
• Two weeks later you buy a 12 month subscription, renewing it on the 2nd of May 2010

That this means is the 1 year tenure will NOT be on the 18th of January 2011.  It will be 2 weeks after that date, due to the 2 weeks of having a silver account. 

Zen has explained it perfectly. Nice job mate.

Also, the initial 30-day free trial doesn't count toward your Gold tenure, if you started your profile with that (as many of us did). So that can be another month offset from your total.

just testing mine lol

should be more than a 1, I have had since 2006 and have had many 12 month subs. hmmm

Hi NlTESHADE! I'm very appreciative of your willingness to help! In the future though, please remember to check the time stamp of the original post and don't bump threads that are months old (even if someone else has replied before you). It is likely that these issues are older, already resolved, and not likely to help the OP. Thanks for understanding!