But it isn't just that statistic. Ofcom's latest Communications Market Report - obligatory reading for anyone in media - reveals a complex picture of swiftly changing behaviour, particularly among the young.
The report confirms they watch less television, listen to less radio and read newspapers and magazines less than they did, as well as less than older sections of the population. Their media time is increasingly spent online, listening to iPods and using their mobile phones. The internet, the report states, now "plays a central role in daily life" with more than 70 per cent of 16- to 24-year-olds taking part in social-networking websites.
Unsurprisingly, advertising revenues are migrating in the direction of the internet too, with an eightfold real growth between 2001 and 2005.
All this is enough to give "old media" businesses the vapours. Since commercial TV appeared more than 50 years ago, there have been no more rapid or titanic shifts than those highlighted by this report. Change has tended to be slower and less dramatic in scale than that which we are witnessing now.
And yet Ed Richards, the chief operating officer of Ofcom and a front-runner to step up to chief executive, says this will not mean the end for established media. "We are seeing an adjustment as a new medium becomes more and more significant in people's lives," Richards says. "Other media will have to adjust and have to respond as they have been doing to that threat, and to respond in the way they use and position their current media. But we don't think any media will die as a result of this."
This makes good sense. At least at an industry level, it seems inconceivable that an entire medium will wither and die as a result of the internet's prodigious growth. But those companies that find an effective way to harness the internet will be the winners. Media owners that fail to develop in this way will find the emerging world depicted in the Ofcom report more challenging.
No-one knows this better than the departing Ofcom chief executive, Stephen Carter. How fascinating it will be if his next job is to take the helm of perhaps the UK's archetypal "old medium", ITV.