Foreign volunteers help the police of Beijing's Dongcheng District advocate laws and regulations concerning foreigners in China. [File photo]

The country carries out a national population census every 10 years, and the previous five censuses only covered people with the nationality of, and living in, the People's Republic of China.

The population census in 2000 showed the world's most populous country had 1.29 billion people.

According to the National Population and Family Planning Commission, the population on the Chinese mainland will reach 1.39 billion by the end of 2015, among which as many as 700 million people will be living in urban areas, exceeding the country's rural population for the first time.

The number of people aged 60 or over is expected to annually increase by 8 million to 200 million by the end of 2015.

This year, the theme of World Population Day was Everyone Counts, which emphasizes the role of good demographic data in planning public facilities and making evidence-based population policies for the future.