ITV1 has slumped to an average audience share of 23.7%, down from 40% in 1993. BBC One's audience has dwindled to 25.6% in 2004, down from 32.7% a decade ago.
Ofcom's figures show clearly that the two main terrestrial channels' audiences are decreasing steadily as multichannel TV grows. Multichannel audiences surged from 6.1% in 1993 to 23.6% in 2004.
The growth in multichannel viewing can be attributed to the increasing penetration of digital TV and cheaper satellite carriage deals.
BBC Two and Channel 4 have remained relatively steady, commanding an 11% and 9.4% audience share respectively.
Five's audience has climbed steadily since its launch in 1997. It now commands a 6.5% share.
There was some better news for BBC One in Ofcom's report. A third of viewers said the corporation's flagship channel was the one they would choose if they only had one station.
The report also revealed DVDs have replaced VCRs as the main tool for watching pre-recorded material.
Interactive TV is growing with the development of digital TV. Some 43% of viewers have accessed interactive television services via their remote controls and 21% do so at least once a week.
Four out of five digital viewers claim never to have bought goods or services via their remote control and only half thought services such as e-mail, games and internet access delivered through the TV were attractive. This figure rose to 69% of 16- to 24-year-olds.
Ofcom also found that 39% of viewers bought pay-per-view films and 24% bought pay-per-view sport.
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