China's population grew by 8.1 million people - or 0.63 percent - last year to 1.307 billion, the government's State Bureau of Statistics reported Thursday.

There were 106.3 men for every 100 women, the bureau said on its Web site.

The figures are the result of the "1 Percent Sample" - a government mini-census of some 17 million people that was conducted midway between a nationwide census done once each decade.

Experts believe the true population is bigger than reported by tens of millions of people and that the male-female ratio is even more lopsided, with as many as 120 men to 100 women in some areas.

The government declared a baby boy born in January 2005, to be the Chinese mainland's 1.3 billionth citizen.

China has tried to limit population growth and ease the strain on scarce farmland and water supplies by enforcing birth-control rules for two decades that limit most urban couples to one child and most rural families to two.

The government says that without that policy, the population would be larger by some 300 million people.

But many families, especially in the countryside, have extra children and fail to report the births, leading to suggestions that census-takers are undercounting the population.