 From the beginning, those involved in the gathering of written data sought to make the BNC a balanced corpus, and hence looked for data in various mediums.90% of the BNC is samples of "written corpus" use.These samples were extracted from regional and national newspapers, published research journals or periodicals from various academic fields, fiction and non-fiction books, other published material, and unpublished material such as leaflets, brochures, letters, essays written by students of differing academic levels, speeches, scripts, and many other types of texts.