[填空题]The press is constantly reminding us that the dramatic increase in the age of our population over the next 30 or so years will cause national healthcare systems to collapse, economies to crumple under the strain of pension demands and disintegrating families to buckle under increasing care commitments. Yet research at Oxford is beginning to expose some of the widespread myths that underlie this rhetoric. Demographic ageing is undoubtedly a reality. Life expectancy in developed countries has risen continuously over the past century, increasing the percentage of those over the age of 60 relative to those under the age of 15. By 2030 half the population of Western Europe will be over the age of 50, with a predicted average life expectancy of a further 40 years. By then, a quarter of the population will be over 65 and by 2050 the UK’s current number of 10,000 centenarians are predicted to have reached a quarter of a million. Some demographers have even suggested that half of all baby girls