China's floating population - composed of people who live in an area different from where they have a hukou (permanent residence permit) - increased by 10 million last year to reach a total of 221 million, according to the National Population and Family Planning Commission.

Nearly 43 percent of the population was born after 1980 and migrant workers account for almost 75 percent of it, Li Bin, head of the commission, said at a recent conference in Guangzhou, capital of South China's Guangdong province.

In the next three decades, another 300 million people from rural areas are expected to find work and take up residency in cities and towns.

At the same time, more and more migrant workers are flocking to inland cities, partly reversing a trend in which waves of people had moved to coastal regions in search of jobs, Li said.

Of the floating population, more than half settled in a city for more than three years and 66 percent brought their spouses, children and parents to live with them, according to statistics from the National Population and Family Planning Commission.

Most young people in the floating population hope to remain in big cities, Li said.

The commission's statistics also indicate that nearly 80 million women in the floating population are of childbearing age.

"The younger generation is becoming the majority of the floating group," Li said. "They have increasing demands for public services such as prenatal and postnatal care and reproductive health checkups."

Li said a priority should be placed on ensuring the floating population has the same access to basic public services granted to those who have hukou in cities.

By 2010, more than 90 percent of the cities in the country had set up organizations to provide public services for the floating population, according to Li.

The previous year, the National Population and Family Planning Commission had started a project in 49 cities to spread information about family planning services and to better manage the floating population.

The project is aimed mainly at helping local branches of the commission learn whether women migrant workers are pregnant. It is to expand into all mainland cities within three years.

Qiao Xiaochun, a population expert with Peking University, said establishing such a system will help authorities count the exact number of newborns within the floating population and better understand the migrations of such people.

But Qiao said gathering information about pregnancies isn't easy.

"Female migrants are required to register at local population and family planning offices, but very few will do so," he said. "Instead, office workers will carry out the registrations through door-to-door visits."

Li said the National Population and Family Planning Commission is working to perfect the network. Already, information has been collected about 120 million members of the floating population and put in databases established in 29 provinces, autonomous regions and municipalities, she added.