BEIJING - The annual growth of China's urban fixed-asset investment continued to cool in 2014 to 15.7 percent, down from 19.6 percent in 2013, the National Bureau of Statistics (NBS) announced on Tuesday.

China's gross domestic product (GDP) grew 7.4 percent in 2014, registering the weakest expansion in 24 years.

Slower growth in fixed-asset investment, which used to be a strong engine for China's fast economic growth, is seen as a key factor in the slower growth in GDP.

Urban fixed-asset investment expanded to 50.2 trillion yuan ($8.2 trillion) at the end of 2014, bureau data showed.

The growth rate was 0.1 percentage points lower than that of the first 11 months of 2014, according to the NBS.

In 2014, fixed-asset investment from the private sector, which accounted for 64.1 percent of total fixed-asset investment, registered a faster growth rate than the total, at 18.1 percent.

Although the growth of private investment also cooled in the year, by 5 percentage points from 2013, its share in total fixed-asset investment went up 1.1 percentage points, the data showed.

The data also showed fixed-asset investment by foreign businesses declined by 0.3 percent year on year in 2014, compared to a 4.5 percent increase for 2013.

Investment in the primary industry hit 1.2 trillion yuan, up 33.9 percent from 2013, while investment in the secondary industry amounted to 20.4 trillion yuan, up 12.9 percent year on year. Investment in the tertiary industry expanded 21.5 percent year on year to 8.7 trillion yuan.

Investment in China's western regions grew by 17.5 percent year on year, followed by 17.2 percent in the central areas and 14.6 percent in the east.