The new EPA fuel economy stickers have taken over car dealers and while their lower numbers are probably not a very good marketing tool, they are a more accurate gauge of consumption and cost.
The former 30-year-old system of determining fuel economy was replaced this year by a measure that takes into account 2007 concepts like using the A/C and traffic.

Changes in percentages appear to affect larger numbers more. A small car that got 45 mpg may look like it is getting worse mileage than an SUV that gets 10 if both numbers are skewed 20%. Hybrid numbers have been affected most because they were judged based on standards developed when a Chrysler was a Newport.

Be nice to the car salesman. The cars haven't changed, just our perception.