I actually think my mileage is about the same, but the symptoms appear sooner. I used to be able to go to about an 1/8 of a tank, then about a 1/4, and now about 3/8. I also am putting in less gallons when I'm filling up, so I know it's happening at higher fuel levels, not just the gauge going derpy. I usually get worse gas mileage in the winter here, but it's starting to warm up so I expect to be back in the low to mid 30s soon. Wintertime driving usually lowers to high 20s. It was the same in my ES too.