Just getting my new 2017 MKZ Hybrid broke in but after 4700 miles my lifetime mileage is 42.3 MPG (actual mileage, not what the car's computer.) This included one 1200 mile highway trip at 70-75 MPH which puts a significant hit on mileage. My normal commute of 18 miles one way on two lane highways and city streets is ideal for a hybrid. My best tank so far has been 46.6 MPG and the lowest was 36.1 MPG. My driving style is mostly engage ACC at the posted speed limit and sit back and enjoy the ride.
My previous car was a 2013 Ford Fusion Hybrid and my cumulative mileage when I traded it at 63,000 miles was 45.7 MPG.