A centenarian is a person who lives to or beyond the age of 100 years. Because current average global life expectancies are less than 100, the term is invariably associated with longevity. A supercentenarian is a person who has lived to the age of 110 or more, something only achieved by about one in 1,000 centenarians. Even rarer is a person who has lived to age 115 – as of March 2013[update], there are only 30 people in recorded history who have indisputably reached this age, of whom only Jiroemon Kimura and Misao Okawa are still currently living. In 2012, the United Nations estimated that there were 316,600 living centenarians worldwide.