BEIJING, Jan. 19 -- China's economy grew 6.9 percent year on year in 2015, the slowest annual expansion in a quarter of a century, but is still in line with the official target, according to data from the National Bureau of Statistics (NBS) on Tuesday.

Growth in the fourth quarter came in at 6.8 percent year on year, the lowest quarterly rate since the global financial crisis, the data showed.

The Chinese government targeted an annual economic growth of around 7 percent for 2015.

The country's gross domestic product (GDP) reached 67.67 trillion yuan (about 10.3 trillion U.S. dollars) in 2015, with the service sector accounting for 50.5 percent, the first time the ratio exceeded 50 percent, according to the NBS.

China's economy still "ran within a reasonable range" in 2015, with its structure further optimized, upgrading accelerated, new growth drivers strengthened and people's lives improved, NBS chief Wang Baoan told a press conference.

However, the country faces a daunting task in deepening reforms on all fronts and needs to step up supply-side structural reforms, he said.

Major economic indicators softened in 2015, with industrial output growth slowing to 6.1 percent year on year from 8.3 percent in 2014, NBS figures showed.

Urban fixed-asset investment continued to cool, expanding 10 percent year on year, compared with 15.7 percent in 2014. Retail sales rose 10.7 percent, down from 12 percent registered in 2014.