It turning out that prices for diesel exhaust fluid are one of the few things in trucking that you can count on remaining nearly the same month after month.

The national average for tote refill prices decreased by 1 cent in the U.S. to $1.87 per gallon and increased by 1 cent in Canada to CA$0.55 per liter this month compared with November, according to new data from the company Integer Research and its DEF Tracker.

The national DEF truck stop average pump price remained stable at $2.79 per gallon in the U.S. This has been the average price since November 2012. In Canada, the pump price has also remained unchanged at CA$0.80 per liter since October 2011.

Atlanta, Nashville and St. Louis  posted the lowest average prices for DEF tote refills, while the highest average prices for totes and for the other delivery modes were found in metropolitan areas in the Central & Southern regions of the U.S.

More information about the DEF tracker is available online