Newer Cummins with Exhaust Fluid

I have a 2014 Cummins CC Laramie 4x4 2500. Around town it averages right at 15 hand calculated, and about 18 at 75 on the highway. Overall mileage is about the same as my old 2005 5.3 GMC Sierra. Towing the 10,000 pound trailer at 65-70 it drops down to around 11. DEF system runs a 2.5 gallon jug about every 1000 miles. No DEF problems in 11,000 miles, I am just amazed at how clean the inside of the exhaust pipe stays. I know that emissions control is a sore subject for some people, but I have grown quite fond of breathing and the new generation of diesels not belching black smoke all the time makes that a little easier.