Average retail gasoline prices in Michigan have fallen 7.5 cents per gallon in the past week, averaging $3.22 per gallon Sunday, according to GasBuddy’s daily survey of 4,913 gas outlets in Michigan.

This compares with the national average that has not moved in the past week to $3.26 per gallon, according to gasoline price website GasBuddy.com. Including the change in gas prices in Michigan during the past week, prices Sunday were 28.5 cents per gallon lower than the same day one year ago and are 22.4 cents per gallon lower than a month ago.

The national average has decreased 9.3 cents per gallon during the past month and stands 6.8 cents per gallon lower than this day one year ago.

“With the fresh start of 2013, many motorists have begun seeking information on where gasoline prices will be going for the upcoming year,” said Patrick DeHaan, a senior petroleum analyst for GasBuddy.com. “GasBuddy will be releasing its 2013 forecast this week, available on the GasBuddy Blog, which will highlight not only where we expect gasoline prices to go, but new this year is our diesel forecast, just more tools to help motorists budget and be prepared for what lies ahead,” DeHaan said.