WASHINGTON, D.C. --- Last week, retail gasoline prices hit a record high for a January, shooting up 5.6 cents from the previous week to reach an average of $3.109 per gallon, as of Jan. 7. That's 80.3 cents above a year ago, the U.S. Energy Department's Energy Information Administration (EIA) reported last week. Prices rose throughout the country, with the Midwest showing the largest regional increase of 6.9 cents to $3.101 per gallon --- 89.1 cents per gallon more than last year. The East Coast price rose 5.9 cents to reach $3.124 per gallon. The Gulf Coast price jumped 5.7 cents to $2.977 per gallon, the EIA reported. The Rocky Mountains' average price gained 2.9 cents to settle at $2.950 per gallon, the lowest regional price. The West Coast continued having the highest regional price --- it rose 2.9 cents to $3.247 per gallon. The average price for regular grade in California climbed to $3.328 per gallon, 3 cents more than the previous week. The average price for retail diesel fuel increased for a second straight week, to $3.376 per gallon --- 3.1 cents over a week earlier and 83.9 cents higher than the same period last year. All regional diesel prices were higher, with the largest regional increase found on the East Coast. The East Coast price rose 3.7 cents to reach $3.436 per gallon. The New England sub-region's diesel price reached $3.644 per gallon, over 97 cents more than a year ago. The Midwest diesel price rose 3.6 cents to $3.345 per gallon. The Gulf Coast diesel price grew by 2.5 cents to $3.318 per gallon. The Rocky Mountain price moved up 0.7 cent to $3.276 per gallon and was the lowest regional price. The West Coast added 2.3 cents to settle at $3.474 per gallon. California diesel prices moved up 3.5 cents to $3.526 per gallon, the EIA said.