New York(CNN Business)US drivers got a slight — very slight — break on prices this weekend as the AAA average for a gallon of unleaded gas fell below the $5 mark. The average price Sunday was $4.98 a gallon, down from $4.99 in Saturday's reading. The average gas price had been $5 or above for the previous seven days, the first time on record prices crossed that mark. It hit a high of $5.02 a gallon on Tuesday and has declined by a fraction of a penny each day since then.