Statistics from the sixth national census released on April 28 offer important information for better policymaking.

The results show that the pace of China's population growth is slowing.

According to the census, China's population was 1.34 billion, an increase of 73.9 million, or 5.84 percent in the 10 years since the fifth national census. This represents an average annual growth rate of 0.57 percent, noticeably lower than the average annual growth rate of 1.07 percent from 1990 to 2000.

In fact, China's annual population growth rate has been decreasing since 1987, which suggests that a negative population growth will come earlier than expected, and the population peak will be lower than expected.

As early as the 1990s, the total fertility rate of China's population had declined below the level of population replacement.

To some extent, the situation can be attributed to the intensified competition for those young parents born in the 1980s and 1990s, and the skyrocketing cost of raising a child. Another factor for the decreasing birth rate is the country's huge migrating population. The sixth national census found 116.99 million people now stay in places away from their hometown.

Thanks to all these elements, China's average family size has decreased from the 3.44 people per household recorded by the previous census in 2000 to the current 3.1 people per household.

In the long run, such a low birth rate will create uncertainties for sustainable development. Past experience shows the longer a low birth rate lasts, the more harm it causes to a country's sustainable development.

Another important message the census results deliver is the unbalanced population structure.

China's aging population poses another serious challenge, as the first generation of people born under the family-planning policy will reach retirement age in three decades. Society needs to provide adequate services, such as homes for the elderly and healthcare. Elderly people in the past could depend on their families for support, but times are changing and the government will have to provide more and more support for the elderly in the future.

Attention should also be paid to the skewed sex ratio, which is still worsening due to the continued, but declining, preference for a boy child.

The latest census found that the sex ratio at birth (where female = 100) reached 118.06, 1.2 percentage points higher than the fifth census data in 2000. Some experts estimate that between 1983 and 2010 there were 41 million more boy babies born than girls, and about 24 million men will not be able to find women to marry in the next 10 years. This requires the government to continue their efforts to adjust policy and strengthen the supervision against gender selection.

The author is a professor of demography at Peking University.