The average price of a gallon of gasoline in the United States fell 13.3 cents in the past two weeks, dropping to its lowest level since late April 2009, according to the Lundberg survey released Sunday. Prices for regular grade gasoline fell to $2.07 a gallon in the survey dated Jan. 23 from the previous survey on Jan. 9. The recent drop has taken prices down more than $1.24 a gallon from the same period a year ago, a decline driven by losses in the crude oil market from its June peak. However, Lundberg noted that the drop in prices was less steep than it had been in previous periods, suggesting a bottoming-out or increase in retail gasoline prices could be looming.