RAM 1500 Ecodiesel, anybody seen one in the wild?

I was able to find a Dodge 2500 straight cab with an 8' box and 12v engine. My stats this week were 18 empty and 12 towing. Nothing much has changed since my first Dodge 2500 I bought 20 yrs ago. If diesel supposedly get 20% better mileage, then why haven't I seen it? I've had two other major branded diesel trucks in those same years that got worse mpg on diesel, than on gas. My 318 gasser got better 22/18 empty/towing.