Iran is a diverse country, consisting of many different religious and ethnic groups that are unified through a shared Persian language and culture.
Iran's population grew rapidly during the latter half of the 20th century, increasing from about 19 million in 1956 to around 75 million by 2009. However, Iran's birth rate has dropped significantly in recent years, leading to a population growth rate—recorded from July 2012—of about 1.29 percent. Studies project that Iran's rate of growth will continue to slow until it stabilizes above 105 million by 2050.
Iran hosts one of the largest refugee populations in the world, with more than one million refugees, mostly from Afghanistan and Iraq. Since 2006, Iranian officials have been working with the UNHCR and Afghan officials for their repatriation. According to estimates, about five million Iranian citizens have emigrated to other countries, mostly since the Iranian Revolution in 1979.
According to the Iranian Constitution, the government is required to provide every citizen of the country with access to social security that covers retirement, unemployment, old age, disability, accidents, calamities, health and medical treatment and care services. This is covered by tax revenues and income derived from public contributions. According to the World Health Organization, Iran ranked 58 in national health metrics and 93 in the overall performance of its healthcare system in 2000