Pump prices took a dip over the past week, according to an Energy Information Administration report released today.

Retail regular gasoline prices clocked in at a national average of $3.547 per gallon for Sept. 16, $0.04 below last week's price tag. Midwest prices dropped the most ($0.085), while the West Coast defied national trends with a $0.103 increase in gas prices.

Compared with a year ago, pump prices are down $0.331. 

Source: EIA.gov 

Over the past week, average retail diesel prices took a slight $0.007 dip to $3.974 per gallon. On a regional basis, the East Coast and Gulf Coast both notched the largest drops at $0.009, while the West Coast prices fell just $0.004.

Over the past year, diesel prices have dropped $0.161.

Source: EIA.gov. 

At these latest prices, the West Coast pays the prettiest penny for gasoline ($3.90) and diesel ($4.138). On the other end, the Gulf Coast can guzzle gas for just $3.301 and diesel for $3.889 per gallon.

Editor's note: A previous version of this article contained incorrect information on diesel prices.