The U.S. trade deficit narrowed much more than expected in October, as exports rose a robust 3.2 percent and imports declined slightly in the face of slackening demand for industrial and petroleum products, a Commerce Department report showed on Friday.

The trade gap totaled $38.7 billion, down from a revised estimate of $44.6 billion for September. Analysts surveyed before the report had expected the October trade deficit to narrow just slightly to about $43.60 billion.

The smaller-than-expected deficit could boost estimates of U.S. fourth-quarter economic growth because it implies a larger share of U.S. demand is being met by domestic production.

However, on an annual basis, the trade deficit has widened sharply this year and could surpass $500 billion when final figures for 2010 are available. Last year, in the midst of the global financial crisis which put a squeeze on world trade, the U.S. trade gap narrowed about 46 percent to $374.9 billion.

Record exports to China and Mexico in October helped push the overall export tally to $158.7 billion, the highest since August 2008. Exports to the European Union and Japan also showed growth.

Overall U.S. imports fell 0.5 percent to $197.4 billion, led by drop in imports of industrial supplies and materials and the lowest petroleum imports since November 2009.

Despite the overall drop, imports from Mexico were the highest on record and imports from Japan and the European Union wer e the highest in two years.

Imports of advanced technology products also set a record.

Despite record exports to China in October, the U.S. trade deficit with that country in the first 10 months of this year was $226.8 billion, up 20.3 percent from the year-earlier period.