The number of working-age people in China decreased by 3.45 million to 937.27 million in 2012, according to the National Bureau of Statistics (NBS) Friday.

Figures released also showed that country's urbanization rate continued to rise.

It is first time the country has recorded an absolute drop in the working-age population in "a considerable period of time", said Ma Jiantang, NBS director, at a press conference.

"We need to pay serious attention to this," he said. He believes the causes lie in China's changing fertility rate.

The working-age population, which covers ages between 15 and 59, accounted for 69.2 percent of the country's total population in 2012, down 0.6 percentage points from 2011, the year in which the rate for the first time declined, said Ma.

Ma said he expects China's working-age population to decrease "steadily and gradually" over a long period or "at least before 2030."

Meanwhile, China's urban inhabitants accounted for 52.57 percent of the country's total population at the end of 2012, up 1.3 percentage points from a year earlier, NBS data showed.

China's population stood at 1.354 billion at the end of last year, increasing 6.69 million in 2012, according to the NBS.