程阳：中国人口年龄性别结构

China's Population by Age & Sex, 1950 - 2050

男 Male           (population in 1000人)          Female 女

       In this animated population pyramid one can watch population change in China unfold over a 100 year period - between 1950 and 2050.
       For the period 1950 to 1995 the pyramid is based on population estimates of the UN Population Division; the data for 2000 to 2050 are from the most recent medium variant UN population projection.

       One can see how the "baby boom" generation from the 1960s and early 1970s "moves up" the age pyramid. The animation also visualizes the aging of the Chinese population, which is caused by the significant fertility decline since the mid-1970s (and the further increase in life expectancy). Within the next 3 decades the number of elderly people in China will increase massively

Source:

United Nations (1999): World Population Prospects. The 1998 Revision. New York (electronic data files)
http://www.iiasa.ac.at/Research/SRD/ChinaFood/data/anim/pop_ani.htm

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Population by Age and Sex, 1950 - 2050;
Proportion Elderly, Working Age, and Children

60+ 以上老人

20-59岁工作者

0-19岁青少孩童

This animation of China's population demonstrates the dramatic change in the country's age structure between 1950 and 2050. While the number of children was increasing rapidly between 1950 and about 1970, it is now declining significantly, due to China's strict one-child family planning program. In the next few decades, China will experience a most serious process of population aging - as can be seen by the shrinking base of the population pyramid and the increasing numbers of people age 50 and above.
 
The bars in the lower half part of the animation represent the percentages of elderly (age 60+), working age population (age 20-59) and children or young adults (0-19) in the population. For instance, it is projected that 31% of all Chinese will be above the age of 60 in the year 2050!

Source:

United Nations Population Division (2004): World Population Prospects, 2004

http://www.china-profile.com/data/ani_pop_1.htm
Note: Animation was produced with the author's DemoGraphics '05 software.

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China's Total Population by Sex and Age, Census 1990

 This population pyramid from the 1990 census tells the dramatic story of China's population history for several decades. For instance, one can see China's "baby boom" which peaked in the late 1960s and early 1970s. It started in the 1950 with those generations that - in 1990 - were 35 to 40 years of age. Then the demographic disaster of the "Great Leap Forward" cut down the cohorts to half their size. The number of people that were 28 to 31 years of age in 1990 (that is, they were born between 1959 and 1963) is substantially smaller than the generations before and afterwards. This severe "cut" in China's age structure is due to the deficit of birth during the Great Leap Forward. It is well known that during severe famine years fertility declines sharply. After the Great Leap Forward births rapidly increased again. The largest cohorts were 16 and 26 years of age in 1990 - that is they where born between 1964 and 1974.

Then the Chinese family planning program obviously took effect. The birth cohorts rapidly declined. Those children, that were between 4 and 11 in 1990, belonged to the smallest birth cohorts after the baby boom. They were born between 1978 and 1985.

At the bottom of the Chinese population pyramid one can again see large cohorts, that were born between 1985 and 1990. They are almost as large as the birth cohorts during the "baby boom" years. However, these large number of birth are just the "echo effect" of the baby boom between the mid-1960s and mid-1970s. The large baby boom generation had their (first) children - and despite the fact, that each couple should have had only one child, the total number of births was high, because of the large number of parents. (In fact the average fertility during the early 1990s was more than two children).

Source:
State Statistical Bureau (1992): 1990 Population Census of China. Beijing
http://www.iiasa.ac.at/Research/SRD/ChinaFood/data/pop/p_23c_m.htm

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http://news.sina.com.cn/z/populationday/index.shtml