No real stats on it, especially as many people (and states, if they get so involved) have different criteria by which they'll define a car as "classic". In Colorado, a vehicle is eligible for "Collector Vehicle" plates simply by being 25 years old, which means that many of the Yugo cars imported into the United States - arguably, some of the worst cars ever and with little collector value - are eligible for these tags. Some may base their definition on how much "iconic" status a vehicle possesses. While the 1964-1/2 Mustang and 1984 Mustang would both be eligible "Collector Vehicles" in Colorado, maybe enthusiasts and collectors would be dismissive of the 1984 model as a "classic" car.
In 2005 there were 241,000,000 Cars registered in the US.
8000
only 20
at least 1000000
2 mine and yours
Yes, there are many US citizens who have cars, but there are many US citizens (like those who are children, those who can't afford cars, etc.) who do not have cars. There are over 250 million registered motor vehicles in the US.
In 2005 there were 241,000,000 Cars registered in the US according to the 2007 Statistical Abstract of the United States http://www.census.gov/compendia/statab/files/enercomm.html
In 2013, there were 254.4 million registered cars in the United States. That does not take into account all the cars that are unregistered or wrecked.
Gun owners aren't "registered" like cars. One estimate is that there are @ 4 million or so gun owners.
There are approximately 250 million registered cars in the U.S. There are probably another 5 million that are stored or just sitting. This is only cars and not trucks and buses.
Cuba?
There are 254.4MM registered cars in the US according to a 2007 DOT study. The US Census estimates there are ~310MM people in the US as of 7/2010. I'm not sure how many are citizens - perhaps ~300MM for a round number. That means ~0.85 registered vehicles for every man, woman and child in the US (or 85 vehicles per 100 people)