What's a reasonable gas mileage for a 4.7 liter 2000 Jeep Grand Cherokee?

I just bought this in the fall. I get 19 or so when I drive 250 miles to
Denver over the passes, but now it's winter and around town I get 10-12 MPG.
It is just block to block stop signs, traffic signals, short trips of a mile
or two here and there--not reaching or sustaining full operating temperature
all the time.

It seems to run fine. A mixture of open road and city driving yields--as
expected--14-15 MPG or so.

I admit--sometimes I like to step on the gas and feel the results. I'm not
shy with the throttle, but I'm not a maniac either.

Dave