oil heat is almost unheard of int he west.
Heating with heating oil is almost unheard of in the west. From the stats I have seen, fewer than 1% of the people in Denver use oil heat, and once you get out of town, it's probably lower.
That "<1%" is probably for folks who use kerosene heaters on occasion.
Most heat here is natural gas, as we've got a lot of it in the west. Out of town, propane, wood, coal...
I do wonder for remove homes in Wyoming and other places how many are not grid supplied, so may use diesel for generators, but I have no data.