By 2050 their numbers could reach 601,000 in the US alone, but most centenarians never expected to reach 100 and many say lifestyle is the secret to longevity.More than a third of US centenarians questioned in a new poll credited their lengthy lives to good living, while 27 per cent said it was due to genes and 23 per cent cite their faith.
Only nine per cent thought they had reached the century mark because of luck.
"Lifestyle choices are consistently very high ranking on what they attribute to their longevity," said Dr Rhonda Randall, chief medical officer of UnitedHealthcare Medicare and Retirement, which commissioned the poll of 100 centenarians.
"It is a very fast-growing segment of the population."
About one in eight Americans were elderly in 1994 but that number is expected to grow to about one in five by the year 2030, according to US Census Bureau.
Despite their surprise at reaching such a grand old age, many centenarians at some point during their lives said they had made a conscious effort to eat well, limit their alcohol intake and avoid smoking.
And half had decided to exercise regularly and minimise and manage stress in their lives.
Although the centenarians had lived through two world wars, witnessed the advent of space exploration and the birth of the Internet, 44 per cent said the one innovation that had made the biggest impact on their lives was the electric refrigerator, followed by the colour television.
The Internet and personal computers were much lower on the list of life-changing discoveries but 13 per cent of 100-year-olds have access to the Internet, six per cent have sent emails and used Google, three per cent have been on Facebook and the same number have texted and used an app on an iPhone.
"These folks are learning new technology and they are using it to stay connected," Randall said in an interview.
If given the opportunity to relive a decade again, 18 per cent would opt for the 1950s, while 12 per cent would prefer to go back to the Roaring Twenties. The least popular decade was the 1980s.
Depending on their political leanings Franklin Roosevelt or Ronald Reagan were popular choices when asked which president they would select among those living or dead to sort out the country's financial woes.
And octogenarian actress Betty White was the hands down favorite guest to invite to dinner, followed by Britain's Queen Elizabeth and her newlywed grandson Prince William.
Nearly half of the centenarians said the best advice they would give to baby boomers turning 65 now would be to spend more time with their families.
"It is also about mental and emotional wellbeing," said Randall. "These folks are saying that they volunteer and are interested in leaving a legacy. They continue to have purpose."
