SANTIAGO, Jan 09, 2012 (Dow Jones) -- Chile's trade surplus in 2011 fell to $10.62 billion versus a $15.86 billion surplus the previous year, the central bank reported Monday.

The smaller surplus was due mostly to an increase in the value of its fuel imports and a drop in copper exports.

Chile imports roughly 98% of the fossil fuels it consumes.

In December 2011, the trade surplus fell to $394 million when compared with $2.45 billion in the same month of 2010.

December exports totaled $6.31 billion, a 17.3% drop from the $7.63 billion exported in December 2010. The decrease was mostly due to lower international copper prices as copper fetched an average $3.43 a pound on the London Metal Exchange in December, versus $4.15/lb in December 2010, according to state copper commission Cochilco.

For the full year, exports rose 13.5% to $80.59 billion versus $71.03 billion in 2010.

Higher annual copper prices helped boost the value of the country's exports as production of the red metal decreased slightly in 2011. Last year, according to Cochilco, copper average $4.00/lb compared with $3.42 in 2010.

Imports, meanwhile, surged 14.3% to $5.92 billion in December from $5.18 billion in the same month of 2010.

In 2011, imports climbed 26.8% to $69.97 billion versus $55.17 billion in 2010.

Not only did the value of fuel imports increase, but robust domestic demand contributed to a gain in the import of consumer goods.

In addition, the central bank reported that Chile's foreign reserves at the end of 2011 totaled $41.98 billion compared with $38.79 billion in reserves at the end of November 2011 and with $27.86 billion at the end of 2010.

In 2011, the central bank implemented a $12 billion currency market intervention program through which it increased it foreign reserves. The bank bought $50 million a day on the local currency market for most of last year.