The number of millionaire households across the globe increased 12 percent in 2010, according to The Boston Consulting Group report, increasing millionaires' share of wealth from 37 percent in 2009.  
 
Despite being at the epicenter of the global financial meltdown, the United States had by far the most millionaires last year, with 5,220 millionaire households, and increase of 1.3 percent from the previous year.  
 
Japan was second with 1,530 and China third with 1,110.