The U.S. merchandise trade deficit dropped to $9.7 billion in November despite rising oil prices as Americans imported fewer foreign goods, including petroleum, the government reported yesterday.

U.S. exports also dipped, but at $33.6 billion they were the third-highest monthly total on record. Commerce Secretary Robert A. Mosbacher called overseas sales "a leading source of strength in the U.S. economy."

In an unusually optimistic reading of the figures, he noted that exports during the first 11 months of 1990 ran 8.4 percent ahead of the previous year's totals, paced by increases of 20 percent in foreign sales of nonautomotive consumer products and 10 percent in foreign sales of capital goods, the high-priced machines that are used in manufacturing plants.

"Despite the spike in petroleum prices, the trade deficit for 1990 is estimated to be the lowest since 1983," when the deficit was $64.2 billion, Mosbacher said.

"We expect continued improvement in 1991, reflecting the increased ability of U.S. industry to compete in world markets," he said.

Even so, the 1990 deficit is likely to be more than $100 billion for a seventh straight year, and the decline is not expected to be as great as most economists predicted a year ago, said William T. Archey, international vice president of the U.S. Chamber of Commerce.

The deficit for the first 11 months of the year stood at $94.9 billion, $7.7 billion less than the total for the same period in 1989.

"Despite a year of record exports, the 1990 deficit will be substantially higher than most experts have been predicting," Archey said.

While imports declined to $43.3 billion in November, a drop of $2.7 billion from the month before, they were still $2 billion higher than the monthly average for the year.

Part of this reflects the continued increase in the price of oil, which was $10.30 per barrel more than the monthly average for the year.

Nonetheless, the bill for oil imports in November declined by $900 million, to $6.3 billion, as the United States brought fewer barrels of the higher-priced oil.

Automobile imports also dropped about 2 percent, to $4.4 billion, from their October level of $4.5 billion, which was a 39 percent increase from the month before.

But Japanese car imports increased by $200 million, to $2 billion.

The improvement of the trade balance with Western Europe, which swung to a $2.4 billion surplus during the first 11 months last year from a $2.1 billion deficit in 1989, was the brightest spot in the U.S. trade picture. There was a more than sevenfold increase in the U.S. surplus with the 12-nation European Community, to $4.8 billion, during the same period as U.S. companies increased their sales in those countries by $10 billion.

Even the large deficit with Japan declined by 18 percent during the first 11 months of last year.

It stood at $3.8 billion in November, a decline of $700 million from the month before, but still higher than the monthly average for the year.