Prius Gas Mileage

I’m having fun computing the long-term gas mileage for my 2007 Prius Touring Edition.  It’s now just under two years old, and here’s the chart for my cumulative performance:

Gas prices (blue line above) have plummeted so much lately that my fill-up last Friday ($2.499) was close to the lowest I’ve paid in two years.  The red line shows the most important number: how many miles I can travel on a dollar’s worth of gas.  Generally it hovers between 10 and 15 miles—at least double what we get from our other car (Honda Odyssey).