Here are the deets for last week:
Bus=16km = 9.94mi = .0994 gallons gasoline
Car=27.3km = 16.963mi = .424 gallons gasoline
Feet=16km = 9.94mi = 0 gallons gasoline *doesn't include walks for fun
So for this week I used 4% of the average amount.
And my average for the last 2 weeks is 3%.