A look at some scientific studies of the present bounds of human longevity from Courant: "It's becoming clear that people who break through the 90-plus barrier represent a physical elite, markedly different from the elderly who typically die younger than them. Far from gaining a longer burden of disability, their extra years are often healthy ones. They have a remarkable ability to live through, delay or entirely escape a host of diseases that kill off most of their peers. Supercentenarians - people aged 110 or over - are even better examples of aging gracefully. ... As a demographic group, they basically didn't exist in the 1970s or '80s. They have some sort of genetic booster rocket and they seem to be functioning better for longer periods of time than centenarians. ... The average supercentenarian had freely gone about their daily life until the age of 105 or so, some five to 10 years longer even than centenarians, who are themselves the physical equivalent of people eight to 10 years their junior. This isn't just good news for the oldest old and for society in general; it also provides clues about how more of us might achieve a long and healthy old age."