Not to be a smart a$$, but does anyone read the owner's manual anymore?
Average fuel economy mode
This mode displays the average fuel
economy by calculating the total fuel
consumption and the total traveled
distance since purchasing the vehicle, reconnecting
the battery after disconnection,
or resetting the data. The average fuel
economy is calculated and displayed
every minute.
To clear the data being displayed, press
the INFO button for more than 1.5
seconds.
Since the manuals are available for download, I usually familiarize myself with the features of the vehicle before taking delivery. Granted it's almost 500 pages but you can get some good info if you read it.