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NEW YORK, Jan 21 (Reuters) - The U.S. manufacturing sector remained mired in a deep slump in December, despite a slight upward revision to factory data, while the service sector was a touch weaker than earlier thought, according to data released by an industry group on Wednesday.
The Institute for Supply Management said its index of national factory activity came in at 32.9 versus the 32.4 it originally reported for December. Both figures, nevertheless, indicate a deep contraction in U.S. manufacturing.
According to the revisions, which cover indexes for 2005 through 2008, December's factory reading is still the lowest in 28 years.
The ISM said its non-manufacturing index came in at 40.1 last month versus the 40.6 originally reported for December.
The services reading is still above November's slightly upwardly revised 37.4. The November number is the lowest in the 11-year history of the gauge.
The level of 50 separates expansion from contraction in the indexes for both the factory and service sectors.
Financial markets displayed little reaction to the revisions. (Reporting by Burton Frierson; Editing by James Dalgleish)