The 767-200's and 300ER's at Delta burn 1 pound of fuel for every 31.0 pounds of weight at optimum altitude and .801 mach. Example; 300,000 pound cruise would equal 9,677 pph fuel flow with the above parameters.
If you're interested, the 400's stretch that to 32.8. The difference is attributed to the raked wingtips.
I fly really fast and take a lot of chances.