China's economy picked up steam in 2017 and grew by 6.9 per cent year-on-year, totalling about USD 12.84 trillion and reversing the downtrend of the world's second largest economy since 2010, official data said here today.

The GDP growth rate eclipsed the official estimates of around 6.5 per cent and even crossed 6.7 per cent witnessed in 2016, which was the slowest in over 25 years, marking the first acceleration in annual growth pace since 2010, as per the data released by the National Bureau of Statistics (NBS).

The International Monetary Fund (IMF) had projected that the Chinese economy would grow by 6.8 per cent in 2017 and 6.5 per cent this year, while the World Bank had estimated the country would grow by 6.7 per cent in 2017 and 6.4 per cent in 2018.

"The national economy has maintained the momentum of stable and sound development and exceeded the expectation with the economic vitality, impetus and potential released," NBS chief Ning Jizhe said in the report.

"We should also be aware that there are still difficulties and challenges confronting the economy and the improvement of quality and efficiency remains a daunting task," Ning said.

China witnessed the fourth quarter growth rate of 6.8 per cent, which remain unchanged from the third quarter, the NBS data said.

The robust economic expansion indicated stability after slowing down since China last posted double-digit growth in 2010.

The NBS data also showed that the Goss Domestic Product (GDP) totalled 82.71 trillion yuan (about USD 12.84 trillion)) in 2017, with the service sector accounting for more than half of the total.

Consumption was the major driver, contributing 58.8 per cent to GDP growth last year showing progress of the government's efforts to rejig the economy from being export driven to that of the one depends on consumption.

The data also showed that China's industrial output registered 6.6 per cent growth year-on-year in 2017, rising from 6 per cent in 2016.

Fixed-asset investment grew 7.2 per cent year-on-year in 2017, which was 0.9 percentage points slower than a year earlier.

Retail sales of consumer goods grew by 10.2 per cent in 2017 as compared to the previous year, a 0.2 percentage points slower than 2016.