WASHINGTON (MarketWatch) -- The U.S. trade deficit widened by 18.2% in September to $36.5 billion, the Commerce Department said Friday. The trade deficit was above the consensus forecast of Wall Street economists of a deficit of $32.0 billion. This is the biggest percentage increase in the monthly trade gap since February 1999. The data suggests that third quarter growth will be revised down from its initial estimate of a 3.5% gain. Imports rose faster than exports in September. Trade activity has recovered to levels not seen since the financial crisis hit in the fall of 2008. The U.S. trade deficit with China widened to $22.1 billion, the largest since last October. The deficit for the year-to-date now totals $274.58 billion, down from $551.44 billion in the first nine months of 2008.