In July last year I calculated my how many bits per second I consume on average 24/7. My calculation was based on a use of around 30 GB per month and resulted in 92.6 kbit/s. Since then my use has increased quite a bit. Last month I transferred almost 70 GB over my VDSL line at home (63 GB down, 6 GB up).
In addition to what I used my VDSL line at home a year ago I have started using it to tunnel all my mobile data traffic through my personal VPN server at home. I assume that required a significant part of the 6 GB of data that flowed in the uplink direction (plus the same amount in the downlink direction due to the round trip nature of the application). A couple of additional gigabytes come from my increased web radio use with my new Squeezeplug. But the vast increase comes from the much increased use of video streaming services as my XBMC home server has made it a lot simpler and fun to access content.
Only little of the content was HD, however, and average stream data rates were somewhere around 2 MBit/s. That's around 720 MB of data for every hour of video streaming. If 30 GB of my monthly data came from video streaming, that's the equivalent of around 41.5 hours of video. Sounds like a lot but divided by 30 days, that's around 1.4h of video per day.
Now imagine how much data would have been transferred over my line with 2 teenagers at home and at full HD resolution…