This is not a small vehicle, most people will get mid teens. Many of Toyota's EPA rating seem to be overly optomistic. Most automakers basically cheat on their EPA tests. ECUs are often reprogramed in favor of high efficiency.
MPG ratings (those number's on the window sticker) are furnished by an outside source, called the Environmental Protection Agency. This info is not provided by the vehicle manufacturer.
Although the EPA's controlled test's have been proven to be the absolute best case scenario... to boldly state that automakers have been cheating to get higher fuel economy ratings is simply not accurate.
If a few extra MPG's are what you require, try an aftermarket cold air intake.
Some of the tests are conducted by the EPA, but some are also conducted by the manufacturer. And yes, there are loopholes that allow automakers to do those things. There are other tricks such as using different fuel blends, or even opening the hood that can increase scores. They may be allowed, but does that make it right?
Besides if you really need more MPG, then you could get a diesel or a hybrid
Honestly, if it as good as they claim it will be, then it will more than double my current MPG and that is something to smile about. Especially at $3.00 a gallon. There is nothing like dropping a hundred dollar bill and not even being able to fill the tank!