sounds like you are resetting it a lot to know what your city/hwy mileage is.... but to answer your question it all depends on how you drive.

my 06 dodge ram had the same computer your jeep has. i reset between fill ups. i averaged 15mpg with a combination of city/hwy driving. on road trips i averaged closer to 20. my wife driving the same truck averaged about 12 city and 16 hwy.