Fuel economy on 04-12 chevy 4x4 colorado

I've had my 2012 Colorado 4x4 Crew Cab since it was new, and have almost 90k miles on it. Fuel economy varies between summer and winter up here due to the use of 4WD in winter. During summer months I get an average of 17-20 MPG, city/highway respectively. During winter months locked in at 4WD High, I get about 16. I've driven a Chevy exclusively for 35 years and find that they keep running well right thru 100k. My oldest truck, used in business to run parts and other misc uses, is just over 130k and still runs like a champ. I keep up on the maintenance with oil changes every 5k-6k miles, and the drained oil is still as clean as it was the first time I changed it, and it still has plenty of pep to get around the lumbering tourist motor home caravans that plague Alaskan highways during the summer.