The rich continue to get richer—and at a faster rate. Global private financial wealth increased by 5.3% to $166.5 trillion last year, according to the Boston Consulting Group. That compares with a 4.4% gain the year before. Some 45% of that $166.5 trillion is held by 18 million millionaire households worldwide. The number of such households in Asia is growing fast. But the U.S. still has the largest share, with more than 7 million millionaire households vs. 2.1 million in China. To see where wealth is concentrated in the U.S., we plotted data from Phoenix Marketing International showing households with more than $5 million in assets by urban area.