Growing wealth and privacy concerns can often result in census takers being treated with suspicion more than cooperation. When census taker Wang Xinwei knocks on the door many Chinese, rather than foreigners, are reluctant to even speak to her. 

"I'm surprised it's the Chinese who are not very cooperative," said the 21-year-old community worker, who was assigned a neighborhood in downtown Beijing. "Some Chinese residents would rather fill out the census at registration centers than let us come into their homes." 

Wang is one of 6 million workers nationwide helping register residents' information for the sixth national population census. 

"Foreigners answer my questions after I introduce myself as a census taker and some even volunteer to help me contact their friends in the same community," she said. Many Chinese, though, "slam the door in my face or refuse to open it". 

Research suggests that this attitude is due to insufficient publicity about the census. 

An online poll by sina.com, a leading news website, showed 47.4 percent of 8,237 respondents said they do not have much knowledge about the census and nearly a third admitted they feel unsafe letting census takers into their homes. 

One of the main reasons for the latter appears to be an increased awareness of privacy, thanks partly to a growing middle-class. 

"People no longer feel they should be managed," said Zhang Yi, a researcher for the Chinese Academy of Social Sciences' institute for population and labor economics. "Instead, they believe they should be served by the government. That is why they say no to census takers before they are convinced their privacy is protected." 

Rapid economic growth over the past decade, coupled with an expanding private sector, has prompted a surge in wealthy Chinese. Sociologists say these people are becoming increasingly protective, especially since ownership of private properties was enshrined in the Constitution in 2004. 

A report by the Chinese Academy of Social Sciences this year said China's middle class - usually people with an annual income of 60,000 to 500,000 yuan ($8,800 to $73,000) - accounts for 23 percent of the country's 1.3-billion population. That figure is expected to hit 35 percent in 10 years. 

Security worries 

Before the 1990s, when most people worked for State-owned companies, where employees often know each other's income, and when the government allocated housing, people did not feel they had much privacy to protect, explained Zhang. 

Today, the new middle class and super rich do not want others to know much about their wealth. 

"Some people who live in up-market neighborhoods don't want to reveal details of their lives because they fear it's more of a check of their properties," said the researcher. 

Another reason for citizens' protective attitudes, say experts, relates to births that remain unregistered to avoid punishment under China's one-child family planning policy. 

Xing Zhihong, deputy director of Beijing's population census, promised privacy will be protected. All the information gathered will be for research only and will be destroyed after the population statistics are compiled and released, he said. 

China conducted its first census in 1953 and the latest will begin on Nov 1. However, Beijing is now conducting a one-month, door-to-door survey in preparation. 

"The preliminary check is aimed at checking people's registration and living conditions. Questions about income and religious affiliation are not included," said Xing, who assured that enumerators have to sign a confidentiality agreement with each interviewee. 

The census chief agreed with Wang that door-to-door surveys are difficult. 

"It is harder to gather accurate information this time than the previous five national censuses," he said. "Especially in top-flight communities, not all residents are willing to reveal personal information." 

Some of the people interviewed by China Daily said they are unwilling to answer questions because they do not feel safe opening the door to strangers. 

"I didn't get any notice from anybody before a stranger who claimed to be a census taker came to knock on my door," said Wang Tingting, 27, who has lived in Beijing for three years and rents an apartment with two other women. "At first I didn't want to open the door because I was home alone. 

"I don't know what would happen if she wasn't a real census worker. News on the Internet said people pose as census takers to try and steal an individual's information." 

Even though Wang was worried, she answered all the questions on the census form, including her name, ID card number, how many people live in the apartment, whether she owned or rented and when she moved in. 

Xing said the government plans to hire local people to conduct the census in their neighborhoods to make community members feel more comfortable. 

Foreigners, as well as people from Hong Kong, Macao and Taiwan, are included in the census for the first time. Most of the 30 or so who talked to China Daily reporters said they feel comfortable taking part because their native countries did similar checks. 

Jeff Levinson, a 28-year-old American who has lived in China for more than three years, said as a foreigner he had to register with the police each time he renewed his visa. 

"The government knows where I live, my passport number and how long I have been here," said the travel organizer. "As for privacy, assuming the questionnaire is similar to that in the United States, I will have no qualms about answering." 

Housing headache 

One of the biggest puzzles authorities hope the census will solve is to clarify the number of empty apartments across China. 

Although opinions differ on the definition of vacant homes and some residents may not be willing to reveal personal details, authorities will still try to get more information on vacant houses through the census, Ma Jiantang, director of the National Bureau of Statistics, was recently quoted as saying by Xinhua News Agency. 

Xing in Beijing said that the census does have questions related to housing but it will not provide an accurate vacancy rate. 

"The population census only aims to check people's registrations and living conditions," he said. 

For people who have been unhappy with the lack of official information on national vacancy rates, the census was viewed as a potential illuminating source. Many experts have called for a tax on vacant homes to curb speculation as some investors hoard large numbers of properties to cause prices to rise. 

As housing prices soared in major cities such as Shanghai and Beijing (recent government measures have helped cool the market), concerns over vacancy rates were rampant. 

The total area of unsold housing across the nation was almost 192 million square meters as of June 30, representing a 6.4 percent year-on-year increase, showed data released on Aug 4 by the National Bureau of Statistics. 

The absence of accurate figures has led many to investigate the exact number of apartment buildings in China that are empty. 

Zhang Jinqiu and Meng Bin, two professors at Beijing Union University, conducted a survey on electricity consumption in more than 50 residential areas in the capital between 2004 and 2006. They found that 27.2 percent of electricity meters in apartment buildings did not register any usage in 2007. 

The survey, which does not include unsold properties, was based on a two-month investigation in the summer, said Zhang Jinqiu. (If consumption for a regular house was less than 10 kilowatts per hour, it was considered empty.) 

Other direct methods by the two, such as reading water meters and counting unlighted rooms in the evening, also provided similar results. 

Feng Ke, director of Peking University's financial properties research center, said complicated methods are not needed to determine vacancy rates, which can be roughly estimated by reading meters from water and electricity companies. 

"It is only a matter of time before a housing survey is conducted, since there is no reliable data to reflect a real picture of the real estate sector," he said. "Without accurate figures, the government will not be able to know how to make a policy." 

Beijing's Chaoyang district government recently released housing vacancy figures, the first of its kind in China, saying that 1.33 million square meters of residential space is vacant. More than half of the space has been empty for at least three years. 

However, officials did not explain how the survey was conducted and failed to make the distinction between unsold housing and unoccupied homes after sales.