To celebrate this anniversary, Microsoft launched an interactive timeline on their British Internet page.
After you added your birthday (works also without being logged in), you can take a virtual tour through Xbox´s history:
As you can see above, there are several statistics at the bottom of the page:
- Total Gamerscore
- Total Consoles sold
- Live community size
You can have a look for yourself here: http://www.xbox.com/en-GB/xbox2001-2011