China’s working-age population shrank in 2012, marking the beginning of a trend that will accelerate over the next two decades and have profound implications for the world’s second-largest economy.

By the end of December China’s population aged between 15 and 59 was 937.27m, a decrease of 3.45m from 2011, according to figures released by China’s National Bureau of Statistics on Friday. “In 2012 for the first time we saw a drop in the population of people of working age ... We should pay great attention to this fact,” said Ma Jiantang, head of the National Bureau of Statistics.

“There are different opinions on whether this means that the demographic dividend that has driven growth in China for many years is now coming to an end,” he added, noting that it was only the start of a long-term trend that would see steady decreases in the working age population each and every year between now and at least 2030.