Average vs Median is a distinction lost on most people.

Super rich Americans skew average wealth upwards. The U.S. has 42% of the world's millionaires, and 49% of those with more than $50 million in assets.

Related: Where in the world are the super rich?

This schism secures us the top rank in one net worth measure -- wealth inequality.

There's one main reason why the average Spaniard or Italian has more to his name than the typical American: real estate.

Home ownership rates are higher in many European countries than in the U.S., giving Joe European more assets to his name than his American counterpart. Plus, it's easier for Americans to borrow money, which eats away at their net worth, said Jim Davies, an economics professor at Western University in Ontario, Canada, and co-author of the Credit Suisse report.

Related: Rich, really rich, and ultra rich

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Americans, meanwhile, are having trouble building wealth because wages have stagnated for more than a decade. Median household income was $51,017 in 2012, compared to $56,080 in 1999, according to the Census Bureau's most recent statistics.

Also, Americans have to pay more out of pocket for basics, such as health care and higher education, reducing their ability to build their nest egg.

"Middle class families haven't been able to save anything," Wolff said.