U.S. average retail pump prices for gasoline increased this week by 3.5 cents per gallon while diesel stayed relatively flat, dropping 1/10th of a penny per gallon, according to data tracked by the Energy Information Administration (EIA).

The U.S. average pump price for diesel dropped 1/10th of a penny to $4.016 per gallon, the agency said, with prices increasing in six out of the 10 regions tracked by EIA. However, the agency noted that this week’s national average price is 11.4 cents cheaper per gallon compared to the same week in 2013.

EIA added that diesel is now over $4 per gallon in six regions as well: New England ($4.389 per gallon); the Central Atlantic area ($4.354), the East Coast ($4.155), California ($4.119), the West Coast ($4.038 when including California’s prices), and the Midwest ($4.019).

Gasoline jumped 3.5 cents this week to $3.479 per gallon, the agency reported, though that price is 28 cents per gallon cheaper compared to the same week in 2013.

Prices for gasoline increased in all regions monitored by the EIA except for the Lower Atlantic, where prices dropped 6/10ths of a penny to $3.370 per gallon.

In related news, prices ticked upwards slightly in February for diesel exhaust fluid (DEF) sold both in the U.S. and Canada, according to data tracked by global consulting firm Integer Research.

In the U.S., the national average for full truckload bulk DEF deliveries increased by three cents to $1.57 per gallon last month, while bulk DEF prices for LTL deliveries jumped up five cents to $1.89 per gallon.

The U.S. national DEF truck stop average price increased by one cent to $2.80 per gallon, while in Canada, DEF pump prices remained unchanged at CA 80 cents per liter; roughly equivalent to $2.721 in U.S. dollars per gallon.

Detroit, MI posted the lowest average DEF prices for all delivery modes, Integer reported, while the highest average prices were found in Denver, CO, Phoenix, AZ, and Salt Lake City, UT.