My commute is 14-15 miles each way, but it's in London. So if I drove it everyday, I would be doing 150miles a week.
But since I work in central London, in the congestion zone, I only drive on nightshifts and Sundays, which accounts for at most 2 days per week.
The other days, I use the train, which costs about £8 per day.
So on average my commuting car mileage is about 60miles per week.