Poster of China's 2015 One-percent National Sample Census. [Photo/Xinhua]

China has started its fourth one-percent national sample census, covering a population of about 14 million.

The census takers are to be equipped with a personal digital assistant or PDA for the first time. They will collect information of the sample households including name, gender, age, ethnic group, educational level, profession, and migration status.

Lu Liping is the head of the Population and Employment Statistics Department under the Shanghai Municipal Statistics Bureau.

"The census takers will use the PDA to submit the data directly to the data server of the National Bureau of Statistics through wireless internet. This method reduces the census cost, protects privacy, and enhances accuracy and timeliness of the data."

The census will cover about five million families in around 60-thousand residential quarters nationwide.

The sample census will help find out changes in the number, quality, structure, layout and housing conditions of the country's population since the country conducted its last national census in 2010.

The census will end on Nov 15.

China, the world's most populous country, has so far carried out six national censuses since 1949.

The country has previously conducted such surveys in 1987, 1995 and 2005.

The Chinese government started in the 1980s to supplement thorough national censuses with sample censuses of one percent of the population.

According to the sixth census, China's population totaled 1.37 billion as of Nov 1, 2010.