Average retail gasoline prices in Michigan have fallen 8.7 cents per gallon in the past week, averaging $3.40 per gallon Sunday. This compares with the national average that has fallen 5.6 cents per gallon in the past week to $3.51 per gallon, according to gasoline price website MichiganGasPrices.com.

Including the change in gas prices in Michigan during the past week, prices Sunday were 2.9 cents per gallon higher than the same day one year ago and are 40.3 cents per gallon lower than a month ago. The national average has decreased 28.4 cents per gallon during the past month and stands 7 cents per gallon higher than this day one year ago.

“Even with Hurricane Sandy causing havoc on refineries and infrastructure in the Northeast, gasoline prices nationally have continued to trend lower,” said Patrick DeHaan, a senior petroleum analyst with GasBuddy.com. “It goes to show how much more significant the Gulf Coast is to this nation’s energy backbone when such a massive storm causes no major rise in the national average. The good news is that average prices will likely continue to decline, perhaps to $3.35 per gallon nationally by Thanksgiving,” DeHaan said.