The People's Republic of China is the second most-populous country in the world and Asia with a population exceeding 1.4 billion, only surpassed by India.

[13] China faces the challenge of an aging population due to increased life expectancy and declining birth rates.

[citation needed] Broadly speaking, the population was concentrated east of the Tibetan Plateau and south of the northern steppe.

The Inner Mongolia, Xinjiang, and Tibet autonomous regions and Qinghai and Gansu comprise 55% of the country's land area but in 1985 contained only 5.7% of its population.

After the interval of the Great Leap Forward, Chinese leaders again saw rapid population growth as an obstacle to development, and their interest in birth control revived.

[citation needed] In 1972 and 1973 the party mobilized its resources for a nationwide birth control campaign administered by a group in the State Council.

By 1973 Mao Zedong was personally identified with the family planning movement, signifying a greater leadership commitment to controlled population growth than ever before.

Yet until several years after Mao's death in 1976, the leadership was reluctant to put forth directly the rationale that population control was necessary for economic growth and improved living standards.

In 1979 the government began advocating a one-child limit for both rural and urban areas and has generally set a maximum of two children in special circumstances.

As of 1986 the policy for minority nationalities was two children per couple, three in special circumstances, and no limit for ethnic groups with very small populations.

[citation needed] In rural areas the day-to-day work of family planning was done by cadres at the team and brigade levels who were responsible for women's affairs and by health workers.

In addition, because city dwellers who were employed in state enterprises received pensions after retirement, the sex of their first child was less important to them than it was to those in rural areas.

The United States Agency for International Development, however, withdrew US$10 million from the Fund in March 1985 based on allegations that coercion had been used.

[citation needed] Observers suggested that an accurate assessment of the one-child program would not be possible until all women who came of childbearing age in the early 1980s passed their fertile years.

China needs to find an appropriate birth policy to optimize the demographic dividend, which refers to the proportion of labor-age population.

[30] The same year, researchers from Victoria University and the Shanghai Academy of Social Sciences forecast that China's population will fall to approximately 525 million by 2100 at current rates.

[40] Total fertility rate by ethnic group (2010 census): Han (1.14), Zhuang (1.59), Hui (1.48), Manchu (1.18), Uyghur (2.04), Miao (1.82), Yi (1.82), Tujia (1.74), Tibetan (1.60), Mongols (1.26).

[41] Source: UN World Population Prospects[43] In 1949 crude death rates were probably higher than 30 per 1,000, and the average life expectancy was only 35 years.

One major fluctuation was reported in a computer reconstruction of China's population trends from 1953 to 1987 produced by the United States Bureau of the Census.

The computer model showed that the crude death rate increased dramatically during the famine years associated with the Great Leap Forward (1958–60).

Also, the policy in force during most of the 1960s and the early 1970s of sending large numbers of high school graduates to the countryside deprived cities of a significant proportion of persons of childbearing age and undoubtedly had some effect on birth rates (see Cultural Revolution (1966–76)).

The right to grow and sell agricultural products for personal profit and the lack of an old-age welfare system were incentives for rural people to produce many children, especially sons, for help in the fields and for support in old age.

Census data obtained in 2000 revealed that 119 boys were born for every 100 girls, and among China's "floating population" the ratio was as high as 128:100.

[53] The People's Republic of China (PRC) officially recognizes 56 distinct ethnic groups, the largest of which are Han, who constitute 91.51% of the total population in 2010.

During the past decades ethnic minorities have experienced higher growth rates than the majority Han population, because they are not under the one-child policy.

Overseas Filipinos (overwhelmingly female) working as domestic workers comprise the largest non-Han Chinese ethnic group in Hong Kong.

[86] In general, rural-urban migrant workers are most excluded from local educational resources, citywide social welfare programs and many jobs because of their lack of hukou status.

[88] Estimations are that Chinese cities will face an influx of another 243 million migrants by 2025, taking the urban population up to nearly 1 billion people.

The other factors influencing migration of people from rural provincial areas to large cities are employment, education, business opportunities and higher standard of living.

[92] The mass emigration known as the Chinese diaspora,[93] which occurred from the 19th century to 1949, was mainly caused by wars and starvation in mainland China, invasion from various foreign countries, as well as the problems resulting from political corruption.