Television broadcasting started in the in 1936 as public service free of advertising. Now there is a collection of free-to-air, free-to-view and subscription services over a variety of distribution media, through which there are over 480 channels for consumers as well as on-demand content. There are six main channel owners who are responsible for most viewing. There are 27,000 hours of domestic content produced a year at a cost of £2.6 billion. Since 24 October 2012, all television broadcasts in the United Kingdom are in a digital format, following the end of analogue transmissions in Northern Ireland. Digital content is delivered via terrestrial, satellite and cable as well as over IP.