Both the BBC and independent television broadcast educational programmes for schools and continuing education programmes for adults. Broadcasts to schools deal with most subjects of the National Curriculum, while education programmes for adults cover many fields of learning and vocational training. Supporting material, in the form of books, pamphlets, filmstrips, computer software, and audio and video cassettes, is available to supplement the programmes. Each year the BBC Open University Production Centre produces around 350 radio and audio programmes and 200 television and video programmes made specially for students of the Open University. The Centre also produces educational and training video materials in collaboration with external agencies such as the Department of Trade and Industry and the Department for Education. The ITC has a duty to ensure that schools programmes are presented on independent television.