Steam TB is evil so I don't have it, but I did the math and if I spent at least 1 hour on TB every day from when I joined till now with an entire year break tossed somewhere in there I'd have around 1825 hours. That's probably on the lower side seeing as I've never taken that long of a break and I've had countless days on TB were I spent way more than 1 hour on the game so I'd estimate around 3k-5k hours in total.