IOWA-MISSOURI -- Average retail gasoline prices have risen once again over the last week in Iowa and Missouri.

As of Sunday, gas prices in Iowa averaged $3.33 per gallon, up 13.6 cents over the last week and up 68.0 cents as the same day a year ago.

Missouri drivers fair a little better, averaging $3.19 per gallon as of Sunday. That is a 19.8 cents per gallon increase over the past week and and up 68.0 cents as the same day a year ago.

The national average has increased 17.0 cents per gallon in the last week to $3.34 per gallon. That is 64.9 cents per gallon higher than the same day a year ago.

For more on area gas prices, visit gasbuddy.com