Average life expectancy has risen globally to record lengths of 73 years for a girl born in 2012 and 68 for a boy, following successes in fighting diseases and child mortality, the World Health Organisation said.
Big advances in the battles against infectious diseases such as measles, malaria, tuberculosis and polio have continued to extend life expectancy, although other factors, such as people's lifestyles, were constraining longevity, the WHO said in its annual statistics report.
The longest life expectancy at birth is for baby girls in Japan, at 87 years, and boys in Iceland, at 81.2 years. Japan, Switzerland, Singapore, Italy and Luxembourg rank in the top 10 for both sexes.
"There are major gains in life expectancy in recent decades and they continue," said Ties Boerma, chief of statistics and information systems at the WHO.
The life expectancy of Chinese women born in 2012 rose to 77 years, while Chinese men could expect to live 74 years. Both sexes enjoy four extra years of life expectancy compared to Chinese born in 2000.
But Chinese life expectancy still lags that of Americans, at 76 for men and 81 for women.
The lowest life expectancy is in sub-Saharan Africa, where nine countries have expectancy of less than 55 for babies of both sexes.
Lifestyle changes leading to heart problems and other diseases are curbing life expectancy in some cases.
However, even in rich countries where people live longest, there is no sign of life expectancy gains slowing down.
"If human life expectancy was capped at population level at around 90 years of life, we would expect to see a slowdown as we approach those limits. We're not seeing that," said Colin Mathers, coordinator of WHO's statistics on mortality.
For the first time, the annual report, the most comprehensive statistical overview of the world's health, measured "years of life lost", a number that takes account of the age when people die as well as the number of deaths, to put more focus on the things that kill more people younger .
Years of life lost to diarrhoea and respiratory infections, the biggest causes of early deaths in 2000, had fallen by 40 per cent and 30 per cent respectively by 2012, when heart disease was the biggest factor in early deaths.
Years of life lost to road injuries increased by 14 per cent between 2000 and 2012, as more people began driving in developing countries.
Life expectancy at birth has increased in almost every country since 1990, and in almost all cases it was higher in 2012 than in 2011, with Botswana, Cote d'Ivoire and Syria among the exceptions.
Another was Pakistan, where life expectancy averaged 65 years in 2012, down from 67 years in last year's report. Mathers said that reduction reflected improved data, which revealed child mortality was 30 per cent higher than previously thought.