China's trade surplus narrowed in 2010 for the second straight year, data showed on Monday, giving Beijing grounds to rebuff U.S. pressure for faster currency appreciation ahead of President Hu Jintao's visit to Washington next week.

The Chinese government will point to the numbers and, especially, heady import growth as evidence of steady progress toward reform of its economy that is giving the world a lift.

The United States will, however, contend that this is happening too slowly, with the politically sensitive bilateral trade gap between the world's two biggest economies widening further in 2010.

But the month of December alone was consistent with what has been a pattern since the outbreak of the global financial crisis more than two years ago. With the Chinese economy growing much faster than the rest of the world, imports outshone exports.

China exports rose 17.9 percent in December from a year earlier and imports increased by 25.6 percent, the customs agency said on Monday.

That left the country with a trade surplus of $13.1 billion, compared with $22.9 billion in November.

The median forecast of economists polled by Reuters last week was for exports to rise 22.5 percent and imports to grow 24.5 percent, resulting in a trade surplus of $20 billion.

"Imports are much stronger than we have expected, indicating that the domestic investment and internal demand are mainly pushing up domestic consumption," said Wang Han, an economist at advisory firm CEBM in Shanghai.

For all of 2010, China's trade surplus was $183.1 billion, down 7 percent from $196.1 billion in 2009. The surplus had fallen 34 percent in 2009 from its pre-crisis peak of nearly $300 billion in 2008.

Beijing has let the yuan rise 3 percent against the dollar since mid-June, when it lifted the currency from a nearly two-year peg that cushioned the economy from the impact of the global financial crisis.

Critics in the United States say that China keeps the yuan cheap to give its exporters an unfair advantage in selling their products to the world.

These long-standing complaints have taken on added potency in the wake of the financial turmoil that has left the United States with an unemployment rate of 9.4 percent.

But Beijing has counseled for patience, repeatedly pledging to reduce its economy's reliance in exports and to seek a more balanced trade relationship with the rest of the world.

It has begun to move in that direction on the back of fast-growing imports of oil, iron ore, copper and other raw materials to fuel its economy.