BEIJING, March 11 -- China's fixed-asset investment rose 13.9 percent to 3.45 trillion yuan (560.06 billion U.S. dollars) year on year in the first two months in 2015, the National Bureau of Statistics (NBS) announced on Wednesday.

The growth rate slowed 1.8 percentage points compared to 2014 at 15.7 percent, according to the NBS.

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 GDP growth.

In the Jan.-Feb. period, fixed-asset investment from the private sector, which accounted for 63.6 percent of total fixed-asset investment, registered a faster growth rate than the total at 14.7 percent year on year.

The data showed fixed-asset investment by foreign businesses declined by 2 percent year on year to 100.7 billion yuan, while that by businesses from Hong Kong, Macao and Taiwan surged 16.9 percent to 116.9 billion yuan.

Investment in the primary industry hit 55.4 billion yuan, up 36.3 percent from a year ago, while investment in the secondary industry amounted to 1.31 trillion yuan, up 11.5 percent. Investment in the tertiary industry expanded 14.8 percent year on year to 2.09 trillion yuan.

Investment in China's central regions grew by 16.5 percent year on year, followed by 13.7 percent in western regions and 13 percent in the east.

Bob Liu, an analyst at China International Capital Corp., said the high interest rate is behind the weakened fixed-asset investment.