Board (HDB). Also, 75.9% of resident households live in properties that are equal to, or larger than, a four-room (i.e. three bedrooms plus one living room) HDB flat or in private housing. Live-in foreign domestic workers are quite common in Singapore, with about 224,500 foreign domestic workers there, as of December 2013. Religion Most major religious denominations are present in Singapore, with the Inter-Religious Organisation, Singapore (IRO) recognising 10 major religions in the city state. A 2014 analysis by the Pew Research Center found Singapore to be the world's most religiously diverse nation. Buddhism is the most widely practised religion in Singapore: 31% of the resident population declared themselves adherents at the most recent census. The next-most practised religion is Christianity, followed by Islam, Taoism, and Hinduism. 20% of the population did not have a religious affiliation. The proportion of Christians, Taoists, and non-religious people increased between 2000 and 2010 by about 3 percentage points each, while the proportion of Buddhists decreased. Other faiths remained largely stable in their share of the population. There are monasteries and Dharma centres from all three major traditions of Buddhism in Singapore: Theravada, Mahayana, and Vajrayana. Most Buddhists in Singapore are Chinese and are of the Mahayana tradition, missionaries having come into the country from China for several decades. However, Thailand's Theravada Buddhism has seen growing popularity among the populace (not only the Chinese) during the past decade. The religion of Soka Gakkai International, a Japanese Buddhist organisation, is practised by many people in Singapore, and mostly by those of Chinese descent. Tibetan Buddhism has also made slow inroads into the country in recent years. Languages Singapore has four official languages: English, Malay, Mandarin, and Tamil. English is the lingua franca and the main language used in business, government, law and education. The Constitution of Singapore and all government legislation is written in English, and interpreters are required if a language other than English is used in the Singaporean courts. Statutory corporations conduct their businesses in English, while any official documents written in a non-English official language such as Malay, Mandarin, or Tamil are typically translated into English to be accepted for use. Malay was designated as a national language by the Singaporean government after independence from Britain in the 1960s to avoid friction with Singapore's Malay-speaking neighbours of Malaysia and Indonesia. It has a symbolic, rather than functional purpose. It is used in