Most Islanders are of either European -only (mostly British) or combined European - Tahitian ancestry, being descendants of the Bounty mutineers as well as more recent arrivals from Australia and New Zealand. About half of the islanders can trace their roots back to Pitcairn Island 30 - . This common heritage has led to a limited number of surnames among the Islanders — a limit constraining enough that the island's telephone directory also includes nicknames for many subscribers, such as Cane Toad, Dar Bizziebee, Lettuce Leaf, Goof, Paw Paw, Diddles, Rubber Duck, Carrots and Tarzan.42 - 30 - The majority of Islanders are Protestant Christians. In 1996, 37.4% identified as Anglican, 14.5% as Uniting Church, 11.5% as Roman Catholic and 3.1% as Seventh-day Adventist. Literacy is not recorded officially, but it can be assumed to be roughly at a par with Australia's literacy rate, as Islanders attend a school which uses a New South Wales curriculum, before traditionally moving to the mainland for further study. Islanders speak both English and a creole language known as Norfuk, a blend of 1700s English and Tahitian. The Norfuk language is decreasing in popularity as more tourists travel to the island and more young people leave for work and study reasons; however, there are efforts to keep it alive via dictionaries and the renaming of some tourist attractions to their Norfuk equivalents. In April 2005, it was declared a co-official language of the island. Emigration is growing as many Islanders take advantage of the close ties between Norfolk and Australia and New Zealand. The sole school on the island provides education to Australian Year 12; therefore, any student seeking to complete tertiary study must travel overseas. Additionally, the small economy of the island causes many skilled workers to emigrate as well.