When I bought my 2002 Santa Fe in January 2002, I decided to keep track of
the gas mileage for a few weeks . Well that few weeks turned into 5 years
and counting.

99.9% of the time I fill up and I burn 87% octane (Regular gas). I "always"
change my oil (10-30 or 10-40)between 5000-7000 kms. 50/50 city/highway
driving. I use cruise on the highway and travel the speed most cars are
driving

Here's the results:

128,250 kms
14,776.6 litres

8.68 kms per litre ( 11.5 litres every 100kms)

or

24.4 miles per gallon