How much CO2 does an office worker generate per year?

I just posted this to friends on Facebook, and it seems a good idea to share it here too, to help with my search:
Hello internet friends. Would a kind soul be able to help me out here?
I’m doing a recorded 20 minute talk in Feb about the environmental impact of building digital products for a free online conference, http://www.sustainableux.com, and I’m looking for leads to work out a number I want to refer to in the talk.
 
I’m after a single number, for the average carbon footprint of a single office worker, working in an office, full time, including their commute, in terms of tonnes of CO2 per year.
 
I know commutes vary wildly, and that’s fine. For this, an average will suffice, as I’m not pretending this will be accurate, just a ballpark figure.
 
I think I’ll mainly be speaking to an audience based in the US, or Europe, based on last year’s viewer figures, so extra points if the number applies to those regions.
 
I know this figure won’t be precise, and I’m aware there are loads of factors that affect this anyway. To the nearest tonne is probably okay.
 
If it helps, please think of this as a number for all those other places that aren’t where you work. I appreciate your office might be super green and virtuous and you’d love to tell everyone about how much you recycle, and how you’re going to eco-heaven, and how everyone is else is terrible but for the purposes of this request I don’t think it will add to the conversation here.
 
Sorry about sounding grumpy in that last para. I’ll be super grateful and give you a shout out in the talk if you can find it.
 
Thanks y’all ❤