Yours is an 06, mine is an 05. To have the lights on, turn the light switch all the way to the left and then I take a black top off of something like a can of spray brake cleaner and put it over the light sensor in the middle of the dash by the base of the windshield.
And yes, you're much safer having your lights on all of the time. And don't worry about using any more fuel, your calculator probably doesn't go out to that many decimal places to figure it out. Or if someone is really worried about this, they'd save more fuel if they went on a diet and lost ten pounds...........
Bill