With 1.4 million millionaire households, the Chinese mainland again seized third place in the 2012 Global Wealth Report published by global management consulting firm Boston Consulting Group (BCG) in late May.

The United States, with its 5.13 million, could still boast the largest number of millionaire households worldwide last year, followed by Japan's 1.6 million.

This year's report, entitled The Battle to Regain Strength, is BCG's twelfth annual report on the global wealth situation.

According to the report, even though the number of millionaire households decreased by a combined 182,000 in the U.S. and Japan over the course of 2011, globally the number grew by 175,000 as many households in developing economies crossed the millionaire threshold, especially in China and India.

The Chinese mainland's number of millionaire households has soared from 850,000 in 2009 to 1.293 million in 2010, whereas in 2011, the number increased by 15 percent.

Also read: Top 15 regions with most ultra-wealthy households 2012

Here are BCG's top 15 regions with most millionaire households:

   Spain

  Number (thousand): 139

2010 number (thousand): 147

2010 rank: 15