National averages for diesel and gasoline continue to follow different pricing paths – with retail pump prices for the former declining as prices for the latter increase – while the bulk cost of diesel exhaust fluid (DEF) ticked upwards even as its truck stop pump prices stayed flat.

According to data tracked by the Energy Information Administration (EIA), the national average retail pump price for diesel declined 1.3 cents to $3.975 per gallon this week, which is 1.8 cents per gallon lower compared to the same week in 2013.

Diesel prices declined in all regions of the country except for the Gulf Coast, where prices increased 4/10ths of a penny to $3.804 per gallon, though that price point remains the cheapest for diesel in the U.S.

The EIA said diesel topped the $4 per gallon mark in four regions, despite each of them posting the sharpest week-over-week price declines in the nation: the East Coast (down 2.1 cents to $4.094 per gallon); New England (down 2.4 cents to $4.255); the Central Atlantic (down 3.6 cents to $4.241); and California (down 2.1 cents to $4.020).

By contrast, the agency noted that national average retail pump prices for gasoline increased this week, climbing 3 cents to $3.579 per gallon – though that’s 6.6 cents per gallon lower compared to the same week in 2013 – with all but two regions of the country posting price hikes.

Prices humped the most in the Lower Atlantic (up 5.9 cents to $3.518 per gallon), the Midwest (3.8 cents to $3.589), and the West Coast without including California (3.5 cents to $3.604). Gasoline prices declined in the Central Atlantic (falling 3/10ths of a penny to $3.585) and the Rocky Mountains (down 6/10ths of a penny to $3.451).

According to the DEF Tracker service provided by global consulting firm Integer Research, U.S. and Canadian bulk DEF prices continued to follow an upward trajectory in March 2014, even though truck stop pricing for the fluid – critical to making selective catalytic reduction (SCR) emission control systems function on diesel-powered trucks – remained relatively flat.

Integer’s data indicated that the U.S. national average bulk DEF price increased four cents to $1.61 per gallon for full TL deliveries and to $1.93 for LTL deliveries, respectively, while increasing five cents to $1.99 per gallon for tote refill deliveries.

The firm added that Atlanta, GA and Cincinnati, OH posted the lowest average bulk DEF prices, while Denver, CO and Phoenix, AZ, posted the highest.

However, Integer said the national DEF truck stop average price remained at $2.80 per gallon in the U.S and at 80 cents per liter in Canada, which roughly equates to $2.721 in U.S. dollars per gallon.

In other news, EIA reported that crude oil inventories at Cushing, OK – the primary crude oil storage location in the U.S. as well as the delivery location for the New York Mercantile Exchange (Nymex) West Texas Intermediate (WTI) crude oil futures contract – decreased 13 million barrels (32%) over the past two months.

The recent drawdown of stocks at Cushing resulted from three factors, according to the agency: The startup of TransCanada's Cushing Marketlink pipeline, which is now moving crude oil from Cushing to the U.S. Gulf Coast; sustained high crude oil runs at refineries in Midwest and Gulf Coast, which are partially supplied from Cushing; and the expansion of pipeline infrastructure and railroad shipments that’s making it possible for crude oil to bypass Cushing storage and move directly to refining centers in East Coast, Gulf Coast, and West Coast.

That being said, EIA noted that Cushing inventories are now at levels that “reflect current market conditions,” and although they are reduced, the levels remain consistent with crude oil supply requirements to meet regional refinery demand.

The agency added that five states and the Gulf of Mexico now supply more than 80%, or 6 million barrels per day, of the crude oil produced in the U.S. Texas alone provided almost 35%, according to preliminary 2013 data released in EIA's March Petroleum Supply Monthly, with North Dakota ranked second at 12%, followed by California and Alaska at close to 7% each and Oklahoma at 4%. By contrast, the federal offshore oil patch in the Gulf of Mexico produced 17%.

Total U.S. crude oil production grew 15% in 2013 to 7.4 million barrels per day, with Texas and North Dakota both leading that growth as their crude oil outputs each increased 29% from 2012. Production gains in both states came largely from shale formations, especially the Eagle Ford in Texas and the Bakken area in North Dakota. In the three years since 2010, North Dakota's crude oil output has grown 177% and Texas's output 119%, each the fastest in the nation.

Three other states that were among the top 10 U.S. producers in 2013 also experienced production growth rates above 20% during the past three years, EIA added. Colorado, which overlies part of the Niobrara Shale, had 93% growth in production from 2010 to 2013; Oklahoma, with the Woodford Shale, had 62% growth; and New Mexico, which shares the Permian Basin with Texas, had 51% growth.

Crude oil is produced in 31 states and two offshore federal regions—the Gulf of Mexico and the Pacific Coast – and of those 33 producing areas, 10 supply more than 90% of U.S. output.

While nine of those top 10 areas were also among the top 10 producers five years ago, EIA noted, their relative contributions have changed. North Dakota has risen from the seventh largest oil producer to the third. The Gulf of Mexico, Alaska, and California, which together in 2008 supplied nearly half of U.S. crude production mainly from conventional oil reservoirs, provided less than one-third of national output in 2013.