Population aging in developed countries

Population aging in developed countries

发达国家的人口老龄化问题

The so-called elderly dependency ratio--- the ratio of older adults to younger adults --- has been rising in the industrialized world for at least 150 years. The pace of increase slowed greatly with the birth of the baby-boom generation after World War II. But elderly dependency will almost certainly rise more rapidly at that generation reaches retirement age.

在过去的150年里，工业国家的老年抚养比（老年人同年轻人的比率）持续上升。二战后，婴儿潮的时候增长速度大大减缓。但是当“婴儿潮”一代达到退休年龄时，抚养比将更加快速的上升。

The changes projected for the United States are not as dramatic as those projected for other areas --- particularly Europe and Japan --- but nonetheless they present substantial challenges. The growth rate of the working-age population in the United States is anticipated t slow from about 1 percent per year today to about 1/4 percent per year by 2035. At the same time, the percentage of the population that is over 65 is poised to rise markedly--- from about 12 percent today to perhaps 20 percent by 2035.

虽然美国的变化不如其他地区明显——特别是欧洲和日本，但是美国仍将面临严峻的挑战。到2035年，美国的劳动适龄人口增长率预计将从现在的每年1%降至每年0.25%左右。同时，65岁以上人口的比率将有明显的上升趋势，从12%增至20%。

These anticipated changes in the age structure of the population and workforce of developed countries are largely a consequence of the decline in fertility that occurred after the birth of the baby-boom generation. The total fertility rate in the United States, after peaking in1957 at about 3.5 births over a woman’s lifetime, fell to less than 2 by the early 1970s and then rose to about 2.1 by 1990. Since then, the fertility rate has remained close to 2.1, the so-called replacement rate--- that is, the level of the fertility rate required to hold the population constant in the absence of immigration or changes in longevity.

发达国家预测出现的这些人口年龄结构与劳动力年龄结构的变化主要是因为“婴儿潮”一代出生而导致的生育率下降。美国的总生育率在1957年达到峰值——每名妇女3.5个孩子，此后在20世纪70年代初降至2个以下，在1990年又回升至2.1个左右。此后，生育率一直保持在2.1左右，所谓的人口更替率是除人口迁移和寿命变化因素之外使人口规模保持稳定所需要的生育率水平。

Fertility rates in Europe , on the whole, and in Japan have fallen far short of the replacement rate. The decrease in the number of children per family since the end of the baby-boom, coupled with increases in life expectancy, has inevitably led to a projected increase in the ratio or elderly to working-age population throughout the developed world.

总的来说，欧洲和日本的生育率远远不及更替率。由于在“婴儿潮”之后家庭出生人口下降，以及预期寿命的上升，不可避免将会造成发达国家的老年人口和劳动力的比率上升。

The populations in most developing countries are likewise expected to have a rising median age but to remain significantly younger, and will doubtless grow faster than the populations of the developed countries over the foreseeable future. Eventually, declines in fertility rates and increases in longevity may lead to similar issues with aging populations in what is currently the developing world, but likely only well after the demographic transition in the United States and other developed countries.

大多数发展中国家的年龄中位数人口同样的也会增加，并保持更加年轻化，在不可预期的将来比发达国家增长更快。最终，这些发展中国家生育率的下降和寿命的增加有可能导致与发达国家类似的人口老龄化的问题，但是可能只会发生在美国和其他发达国家人口转型之后。