Photograph by Andrejs Pidjass/iStock/Thinkstock by Getting Images,

The net worth of every person on the planet adds up to $135.5 trillion.

To put that in perspective, when you divide it by the population of the world, you get an average net worth of $19,000. That's just barely enough for every person to buy a used 2012 Honda Accord with 50,000 miles on it.

This is just one of many facts revealed in a recent report by The Boston Consulting Group. Another interesting tidbit is that there are 13.8 million millionaire households in the world today.

Spurred on by rising equity indexes -- the S&P 500 (SNPINDEX:^GSPC) is up by 37% over the past two years alone -- the United States retained its convincing lead with 5.9 million millionaire households, or 43% of the total. Japan came in a distant second with 1.5 million millionaire households, or 11%.

In light of our collective fascination with the world's wealthiest people, I thought you'd find the rest of this list interesting. What follows, in turn, is a slideshow revealing the 10 countries with the largest number of millionaire households in the world.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.