The national average price of gasoline returned to New Year's levels, falling eight of the past nine days to reach $2.34 per gallon, according to AAA.

Retail unleaded fell 3 cents on the week, and remains 10 cents above its month-ago level and 43 cents higher than a year ago. AAA attributed the slight price decline to less demand and adequate supply, and warned that this downward dip may only be temporary. OPEC is scheduled to release its December monthly output report later this week.

Federal data mirrored AAA's findings. The U.S. Energy Information Administration also reported a 3-cent weekly decline to $2.358 per gallon. Gasoline is 44.4 cents lower than a year ago, according to that data.

The states that have seen the largest price decreases week-over-week include Indiana (13 cents), Ohio (12 cents), Michigan (11 cents), Kentucky (7 cents), and Illinois (6 cents). The nation’s top five most expensive markets include Hawaii ($3.06), California ($2.81), Alaska ($2.77), Washington ($2.74) and Pennsylvania ($2.64).

Meanwhile, the average price of diesel fell 1.2 cents to $2.585. Diesel is now 47.3 cents higher than a year ago.