NEW YORK (Reuters) - The average fuel economy of vehicles sold in the United States hit a record high 23.6 miles per gallon (mpg) for the model year 2012, the U.S. Environmental Protection Agency said on Thursday.

Projections for the model 2013 year indicate a rise of 0.4 mpg, the EPA said, though the agency added that it did not yet have final data for 2013.

The 23.6-mpg reading for 2012 was a 1.2 mpg increase over the previous year and the second largest increase in the last 30 years, the EPA said. The boost is part of a trend that has seen fuel economy increase by 2.6 mpg, or 12 percent, since 2008, and by 4.3 mpg, or 22 percent, since 2004, according to the EPA.

Oil traders and analysts have said that improved fuel economy could curb fuel demand growth. Evidence of this effect should start to appear as drivers replace older vehicles with newer, more efficient models, they forecast.

Automakers reported an 8.9 percent rise in U.S. sales in November from a year earlier with a seasonally adjusted annualized rate of sales reaching 16.41 million vehicles.

(Reporting by Robert Gibbons; Editing by Alden Bentley)