In a recent talk at the Long Now Foundation, Katerhine Fulton noted that there are more than 10,000 Americans with net worth of more than $100 Million. This year, everyone on the Forbes 400 list had at least a billion US Dollars.
The money isn't just in America. China has "27,310 people with private property worth more than 50 million yuan, and 3,220 own more than 100 million worth." The country had 15 billionaires on the Forbes 400 list. Here's a map of the rest of the billionaires.