The figures I mention are ballpark - anyone is welcome to offer exact figures. The New Horizons probe will reach Pluto next July after a 4 billion mile journey. The amount of liquid fuel launching it is about 50,000 gallons. I will take a wild guess that the solid fuel boosters would equate to 75,000 gallons of fuel, not counting oxidizer. So flying at 60,000 to 100,000 mph, New Horizons is hypermiling at over 53,000 mpg!
