I just turned 5k miles on my 2013 and I get 16 or less in city. No mods. Just did a big weekend trip with lots of highway and averaged 24.5. On one leg of the trip I did manage 28 mpg.
I was very impressed with the 21.5 I averaged in the mountains tho. I have both sport packages with the big wheels, which no doubt impacts the city mileage. Just my two cents.