I always thought so funny the american TV shows depicting a 16 years old fighting his parent over his/her first car, and finally getting it.
My brother and I, we shared one small motorbike ^^
http://www.nationmaster.com/country-info/profiles/United-Sta...
So which is it?
816 per 1000 sounds reasonable when you consider how many are childern, live in big cities, are in the military, etc... There are some pretty big classes of people who own no vehicles whatsoever.
If you look at married suburban households the number will almost certainly be over 2. The most common case involves one person driving to work while the other shuffles kids around or has their own job. The public transport option may exist, but is likely inadequate (excessively slow) and undesirable.
In my neck of the woods, the average is probably 4-6 cars per family.