Your best (highest) mph average

Returning from MOA rally last week I averaged 66 mph on a ride over 500 miles. Nearly all slab, but that is way over any previous average of 54 mph on a 600 mile ride from southern BC, Canada. Anyone else average high mph on an over 500 mile ride?

Closed course, professional rider. I loaned my RT to her for this ride.

Average Speed

2011, Broomfield CO to Iowa City IA. I had to go back and look at my ride tale for the departure time (8AM, in the text), arrival time (7:28PM, in the photo) and the mileage (781.2, in the photo); I came up with a hair over 68 MPH for the day. Nebraska and Colorado both have 75MPH speed limits on the interstate highways, so that helps.