By 2006 some 21,388 people were living in the Cook Islands, more than half of them on Rarotonga. But only 13,500 were permanent residents. About 51,000 live in New Zealand, 70 percent were born there, and 42 percent were under the age of 15. About 15,000 Cook Islanders live in Australia. With most of the population living away from the islands, efforts to preserve language and culture are underway in expatriate communities, as well as in the homeland.