Is there a way to see how much time I have logged on multiplayer over the years?

I think there is a way to see how many games you have won over the last couple weeks.
Found Here: http://forum.toribash.com/tori_earnings.php
There is also a way to see how recently you have logged into the forums.
Found Here: http://forum.toribash.com/tori_login_history.php
Other than that, I'm afraid I can't help.

Best bet is to ask iLLepidus:

He did the tb stats every month or so. Ask him for where you are on the list, or how he does it.

http://forum.toribash.com/showthread.php?t=201813