It was not until the 1950s and 1960s that indigenous artists such as Mungo Martin, Bill Reid and Norval Morrisseau began to publicly renew and re-invent indigenous art traditions. Currently there are indigenous artists practising in all media in Canada and two indigenous artists, Edward Poitras and Rebecca Belmore, have represented Canada at the Venice Biennale in 1995 and 2005 respectively. The First Nations peoples of Canada comprise diverse ethnic groups, each with their own musical traditions. There are general similarities in the music, but is usually social (public) or ceremonial (private). Public, social music may be dance music accompanied by rattles and drums. Private, ceremonial music includes vocal songs with accompaniment on percussion, used to mark occasions like Midewiwin ceremonies and Sun Dances. Traditionally, Aboriginal peoples used the materials at hand to make their instruments for centuries before Europeans immigrated to Canada. First Nations people made gourds and animal horns into rattles, which were elaborately carved and beautifully painted. In woodland areas, they made horns of birch bark and drumsticks of carved antlers and wood. Traditional percussion instruments such as drums were generally made of carved wood and animal hides. These musical instruments provide the background for songs, and songs are the background for dances. Traditional First Nations people consider song and dance to be sacred. For years after Europeans came to Canada, First Nations people were forbidden to practice their ceremonies. In the 20th century, the First Nations population of Canada increased tenfold. Between 1900 and 1950 the population grew only by 29% but after the 1960s the infant mortality level on reserves dropped and the population grew by 161%. Since the 1980s, the number of First Nations babies more than doubled and currently almost half of the First Nations population is under the age of 25. As a result, the First Nations population of Canada is expected to increase in the coming decades. The 2006 census counted a total Aboriginal population of 1,172,790 (3.75%) which includes 698,025 North American Indians (2.23%). There are distinct First Nations in Canada, originating across the country. Indian reserves, established in Canadian law by treaties such as Treaty 7, are the very limited contemporary lands of First Nations recognized by the non-indigenous governments. A few reserves exist within cities, such as the Opawikoscikan Reserve in Prince Albert, Wendake in Quebec City or Enoch Cree Nation 135 in the Edmonton Metropolitan Region. There are more reserves in Canada than there are First Nations, as First Nations were ceded multiple reserves by treaty.