According to the WSJ[1], there were 3.1 millionaires in the US in 2010. I'm not sure what he means by "in a random year", but perhaps it means that 1/11 people become a millionaire at some point in their life (even if they don't stay one for long)? Or, he's off by a factor of ten (the coincidence of 3.1MM vs 31MM is hard to discount).
Becoming a millionaire doesn't require an annual income of $400k/yr. Most millionaires probably make far less, (150-250k?), and become millionaires from savings over many years.
"Merrill and Capgemini define millionaires as individuals with $1 million or more in investible assets, not including primary home, collectibles, consumables and consumer durables."
So not including your home, or things you can sell like your car, or collectible ginsu knife set. I guess they do include your self managed IRA though, since that is 'investible.'
Becoming a millionaire doesn't require an annual income of $400k/yr. Most millionaires probably make far less, (150-250k?), and become millionaires from savings over many years.
[1]: http://blogs.wsj.com/wealth/2011/06/22/u-s-has-record-number...