(Bloomberg News) U.S. economic data are outperforming expectations by the most in nine months, a trend Federal Reserve officials may incorporate into their policy statement tomorrow.

The Citigroup Economic Surprise Index, a daily measure of whether economic data is better or worse than economists' projections, improved to 85.7 on Dec. 2, the highest since March 9, after the Labor Department reported an unexpected drop in the jobless rate. The index is calculated on a three-month rolling basis and weighted for the importance of the indicator.

"Most of the economists are missing the underlying strength" in the world's largest economy, said Joel Naroff, president of Naroff Economic Advisors, Inc. in Holland, Pennsylvania. The Fed will "modestly upgrade the economic outlook but change little else."

November unemployment at the lowest level in more than two years and manufacturing running at the fastest pace in five months are among data that may dissuade Fed Chairman Ben S. Bernanke and fellow central bankers from pursuing a third-round of large scale asset purchases. At the same time, the Fed may still see "significant downside risks" for the economy as Europe's financial crisis evolves.

Michael Feroli, chief U.S. economist at JPMorgan Chase & Co. in New York, said in an e-mail to clients that it's "not obvious" policy makers will drop that phrase from their statement. The Fed's Open Market Committee "has already been whistled offsides for optimism a few times in this recovery, and more recently seems to prefer to err on the side of caution."

Still, the Economic Surprise Index has rebounded since plunging in June to minus 117.2, the lowest reading since the recession. A positive reading means that economic figures have been stronger than the median projections in Bloomberg surveys.

"We get these recurring cycles where people get overly optimistic or overly pessimistic but as things go this was a pretty significant one," said Stephen Stanley, chief economist at Pierpont Securities LLC in Stamford, Connecticut.

Stocks dropped as Moody's Investors Service said it will review the ratings of all European Union countries and Intel Corp. cut its revenue forecast. The Standard & Poor's 500 Index fell 1.6 percent to 1,234.62 at 10.43 a.m. in New York. Treasury securities rose, sending the yield on the benchmark 10-year note down to 2.01 percent from 2.06 percent late on Dec. 9.

Turkey, which sends almost half its exports to countries in the European Union, said today its economy grew 8.2 percent in the third quarter from the same time last year, more than forecast by economists surveyed by Bloomberg. The pace of growth last quarter was exceeded only by China among the Group of 20 economies.

In Asia, India's industrial output shrank for the first time in 28 months, pushing stocks and the rupee lower on concern faltering growth will force the central bank to suspend its fight against inflation. Production at factories, utilities and mines fell 5.1 percent from a year earlier in October, the government reported today.