Best: 25-6 (50-70 MPH highway). Worst: 14-16 (stop and go with a car full and a trailer full of firewood) If you have a lead foot, you can drive it down to 14-16 city in stop and go. If you baby it and watch your MPG and RPM you can regularly get in the low to mid 20s with about 50/50 city highway. I have learned to drive with the Tachometer rather than the speedo when trying to boost MPGs. Keep it below 1800-2k RPMs and you'll stay around 20mpg. You won't take off from a stoplight, but you'll keep your MPG high.
I took a 1200 mile roundtrip about 1 month ago in a combo of good, dry and poor, snowy highway/freeway. I averaged 23.5 mpg (total miles/total gas purchased) for the trip, with a high of 25.5 mpg on one sunny leg at 65-70 mph and a low of 21 mpg at 45-65 mph on icey/snowy roads. I can see a 2 mpg difference in areas/states that require "winter gas" that contains 10% ethanol.
I have noticed the mpg goes south quickly at speeds above 70 mph.
In our area, the "cheap gas" contains 10% ethanol and you can pay 10 cents per gallon more for "super unleaded" that contains no ethanol - and come out ahead with the extra mpg.
In daily driving (50/50 city/hwy), I average 19-20 mpg in winter and 21-22 mpg in summer.
The engine gets pretty thirsty in true start/stop city driving, since it's not a light vehicle. Since the OP asked about mostly city driving, I'd say in those situations I see an average of about 15-16mpg.