The census released on Thursday showed the population in China, the world's second biggest economy, grew by 5.84 percent from the 1.27 billion in the last census in 2000 and to a level that was smaller than the 1.4 billion some demographers had projected.

The results also showed China is fast urbanizing and becoming older. These trends augur big changes in the labor market in coming years, as the number of potential workers, especially from the countryside, shrinks and the elderly dependent population grows.

The results could encourage the government to relax family planning restrictions that limit nearly all urban couples to one child, while rural families are usually allowed two, said Du Peng, a professor at the Population and Development Studies Center at Renmin University in Beijing.

The proportion of mainland Chinese people aged 14 or younger was 16.60 percent, down by 6.29 percentage points from the number in the 2000 census. The number aged 60 or older grew to 13.26 percent, up 2.93 percentage points.

The figures also showed that China's population is growing more slowly than in the past. Between 1990 and 2000, the total population increased by 11.7 percent.