East Timor (/ˌiːst ˈtiːmɔr/) or Timor-Leste (/tiˈmɔr ˈlɛʃteɪ/), officially the Democratic Republic of Timor-Leste (Tetum: Repúblika Demokrátika Timór-Leste), is a country in Maritime Southeast Asia. It comprises the eastern half of the island of Timor, the nearby islands of Atauro and Jaco, and Oecusse, an exclave on the northwestern side of the island, within Indonesian West Timor. The country's size is about 15,410 km2 (5,400 sq mi).East Timor was colonised by Portugal in the 16th century, and was known as Portuguese Timor until Portugal's decolonisation of the country. In late 1975, East Timor declared its independence but later that year was invaded and occupied by Indonesia and was declared Indonesia's 27th province the following year. The Indonesian occupation of East Timor was characterised by a highly violent decades-long conflict between separatist groups (especially FRETILIN) and the Indonesian military. In 1999, following the United Nations-sponsored act of self-determination, Indonesia relinquished control of the territory. East Timor became the first new sovereign state of the 21st century on 20 May 2002 and joined the United Nations and the Community of Portuguese Language Countries. In 2011, East Timor announced its intention to gain membership status in the Association of Southeast Asian Nations by applying to become its eleventh member. It is one of only two predominantly Christian nations in Southeast Asia, the other being the Philippines.East Timor has a lower-middle-income economy. About 37.4% of the country's population lives below the international poverty line – which means living on less than U.S. $1.25 per day – and about 50% of the population is illiterate. It continues to suffer the after-effects of a decades-long struggle for independence against Indonesian occupation, which severely damaged the country's infrastructure and killed at least 100,000 people. The country is placed 128th on the Human Development Index (HDI).