It was the second straight month in which the deficit narrowed.
The deficit has been narrowing since 1987, when it hit a record $152 billion.
It was the first time since November that the deficit had narrowed.
The overall trade deficit narrowed 12.9 percent in August, to $9.74 billion.
The trade deficit narrowed significantly in the first quarter and business investment shot up substantially.
In December, the deficit with China narrowed nearly 12 percent, to $16.3 billion.
But for 1991, the deficit narrowed to the smallest shortfall in eight years.
But the trade deficit with the rest of the world narrowed sharply on a surge in exports.
Oil, which trades globally in dollars, is a big reason why the deficits have not narrowed.
The trade deficit narrowed sharply in October, to $7 billion, as exports jumped to a new record.