At a national average of $2.59 gal in late December, retail gasoline prices ended 2009 in the middle of their five-year range following a slow price decline since November, explains the Energy Information Administration. The average is down 10cts from Nov. 2 when they posted a high for 2009 at $2.69 gal.

"Although the average gasoline price is currently 94 cents higher than a year ago (when prices had fallen to their lowest level in nearly 4 years), it is slightly below the average of $2.65 per gallon over the 2005-2009 period," said the EIA.

Gasoline prices were relatively flat during the second half of 2009, with the U.S. average holding between $2.46 and $2.69 gal. The 23cts range compares with the $1 increase in the average from January through late June, and the "roller-coaster ride of 2008, which saw a high of $4.11 per gallon, and a low of $1.61," notes the EIA.

"Although the volatility of gasoline prices in recent years has made it hard to define a “typical” pattern, this year’s fourth quarter price path is not unusual," said analysts with the Department of Energy's statistical division.

They note that gasoline demand is the weakest in the first and fourth quarters, with holiday travel typically fueling a year-end uptick.

"Gasoline prices will generally follow this pattern, though the trend may be offset or amplified by changes in underlying world oil markets," said the EIA.

A nearly $9 drop in New York Mercantile Exchange crude futures from Dec. 1 through Dec. 14 had pressured retail gasoline prices in early December. However, crude prices are again on the rise.

"[R]etail gasoline prices remain in decline, if only slowly. How much lower they might go is uncertain, but without a significant shift in current market conditions, we would not be surprised by a weekly average price near $2.50 per gallon sometime this winter," said the EIA.