And there will be more and more elderly as lifespans increase:
"We're living longer because people are reaching old age in better health," said demographer James Vaupel, author of a review article appearing in the March 25 edition of Nature. But once it starts, the process of aging itself - including dementia and heart disease - is still happening at pretty much the same rate. "Deterioration, instead of being stretched out, is being postponed." ... Over the past 170 years, in the countries with the highest life expectancies, the average life span has grown at a rate of 2.5 years per decade, or about 6 hours per day.
It also may be time to rethink how we structure our lives, Vaupel said. "If young people realize they might live past 100 and be in good shape to 90 or 95, it might make more sense to mix education, work and child-rearing across more years of life instead of devoting the first two decades exclusively to education, the next three or four decades to career and parenting, and the last four solely to leisure."
One way to change life trajectories would be to allow younger people to work fewer hours, in exchange for staying in the workforce to a later age. "The 20th century was a century of the redistribution of wealth; the 21st century will probably be a century of the redistribution of work," Vaupel said.