Bought a brand new 2016 Civic
Bought a brand new 2016 Civic EX in Oct 2016. At 800 miles on the odometer we drove interstate (Vegas-SLC) and put on 800 miles round trip. Weather was great, no issues and we averaged 75 MPH. We got 30 MPG. Our car currently has 4000 miles on it and we're driving the same route right now, good weather, no traffic ego button on, etc. we just had to fill up part way and we're averaging 32 mpg.
For reference, we've driven the same route dozens of times in various weather conditions in our 2013 Honda Civic. In that car we always averaged 39-42 MPH. The 2016 is supposed to better gas mileage but it doesn't... taking it to the dealership when we get home.