Just an update on the gas mileage efficiency I've been getting with my 2007 Honda Civic (automatic transmission). The orange line represents the average, which is currently hovering just above 30MPG. The EPA rating was 25/36 so I'm doing pretty well still.
It does look like the efficiency may have dropped a little bit starting around autumn 2011. But it's hard to say for sure since the gasoline formulations change regularly what with the summer/winter mixes and inconsistent ethanol levels.