Average retail gasoline prices in Indiana have fallen 15.9 cents per gallon in the past week, averaging $3.45 a gallon Sunday, according to GasBuddy.com's daily survey of 3,271 gas outlets in Indiana.

This compares with the national average that has fallen 5 cents per gallon in the last week to $3.58 a gallon.

Prices in Jefferson and Trimble counties ranged from $3.34 to $3.35 a gallon this morning. Carroll County prices ranged from $3.36 to $3.49 this morning.

Including the change in gas prices in Indiana during the past week, prices Sunday were 45.7 cents a gallon lower than the same day one year ago and are 29.5 cents a gallon lower than a month ago. The national average has decreased 1.2 cents a gallon during the last month and stands 9.1 cents a gallon lower than this day one year ago.

"While gas prices in Anderson, SC have hit $2.99/gal in the last week, nationally, pump prices have also seen drops amounting to an average drop of a nickle per gallon," said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan.

"The rest of the summer will likely see prices flirting with where they stand today, but more significant relief will arrive around mid-September, when prices nationally could be 10-25 cents a gallon lower than where they are today," DeHaan said.