2008 pruis mpg info screen blank

I'm considering a 2008 prius at a local auction. I'd like to see the MPG history, but all the trip info screen shows is an option to "delete personal information". I'm guessing that the autctioneer selected this after parking the car. I can't drive the car so I'm really curious about what might have happened. Wouldn't there be some MPG history after the car had been moved even a few yards? Is there a way to turn MPG tracking off?