It sort of depends whether you want to consider the mileage as a unit for the entire life of the car, or from this point forward. Since I don't know how long you've owned the car or what you paid for it, let's do a rough calculation of the latter..
Current value - ~$3k?
Salvage value - ~$500, I will assume you are driving this car into the ground as a true Mustachian; for a Civic that should be past 200k, but we will conservatively use that value
Maintenance (oil, brakes, tires, etc. You can nail down a more exact number per MMM's post): $200/year (can be lower or higher based on your car or if you are handy with a wrench/getting deals)
Insurance - $500/year (what I pay for my 2000 civic)
Fuel - $4/gallon at 30mpg
Depreciation cost: (3000-500) = $2500/80,000mi = $.031/mi, none after 200k
Maintenance cost: $200/10,000mi (yearly approximation) = $.02/mi
Insurance: $500/10,000mi = $.05/mi
Fuel - $4/30 = $.133/mi
All told approximately $.235/mi, about as frugal as you can get for car costs, under half of the AAA figure.
This is an approximation and depends on your car and driving habits, but it should be pretty close.