BEIJING, Jan. 9 -- China's producer prices continued to drop in 2015, marking high deflationary pressure on the economy, official data showed on Saturday.

The producer price index (PPI), a measure of costs for goods at the factory gate, dropped 5.2 percent year on year in 2015, widening from a 1.9-percent slip registered in 2014, according to the National Bureau of Statistics (NBS).

In December, the PPI fell 5.9 percent from a year ago, unchanged from that of November and marking the 46th straight month of decline. Last month's PPI also edged down 0.6 percent on a month-on-month basis.

The NBS attributed the decline mainly to price drops in oil and natural gas exploitation, ferrous metal smelting, coal mining and fuel gas supply.

The data came along with the release of the consumer price inflation index, which rose 1.6 percent in December and 1.4 percent in the last year, well below government's full-year target of around 3 percent.

HSBC analyst Qu Hongbin said rising deflation pressure caused by sluggish demand will pose a major risk in 2016 and called for policy easing and supply-side reform to tackle the problem.