Sri Lanka is among the 10 economies with the fastest growing millionaire populations.

Six of the 10 economies with the fastest growing millionaire populations were in Asia, led by Hong Kong and Vietnam, which each saw annual growth of 33%. Others included Sri Lanka, Indonesia, Singapore and India, the the 15th annual World Wealth Report by Merrill Lynch’s wealth management division and consultancy Capgemini said.

Asia’s growth outpaced Europe, where so-called high net worth individuals increased 6% to 3.1 million, and puts it within reach of North America, where the number of wealthy rose 8.6% to 3.4 million.

The report’s findings illustrate how Asia’s economies are growing much more quickly than developed countries and, in the process, minting scores of new millionaires and billionaires. Asia’s growth has been powered by China and India, whose economies grew 9% to 10% last year while European and North American growth was in the low single digits.

“It is entirely conceivable that Asia would overtake North America in the near future,” said Wilson So, a managing director at Merrill Lynch Global Wealth Management. “I would be surprised if that does not happen very soon.”

The U.S., Japan and Germany still account for just over half the world’s 10.9 million wealthy, while China is in fourth place with 535,000, about 58,000 more than in 2009. Australia has moved up one notch to ninth place, edging out Italy, while India cracked the top 12 for the first time. It replaced Spain, which fell to 14th.

While 2010 was the first time that Asia has overtaken Europe in absolute numbers of wealthy people, it is the second year that Asia’s combined wealth was bigger than Europe’s.

The world’s wealthy were worth a total of $42.7 trillion in 2010. Asia’s share of that wealth amounted to $10.8 trillion, putting it in second place for the second year in a row, just behind North America’s $11.6 trillion.

Asia also had a bigger proportion of young millionaires, with 3% aged 30 or under. All other regions had 2% or less.

Globally, women are increasingly in the ranks of millionaires. The report found that 27% of the world’s wealthy last year were women, up from 24% in 2009.

While the majority of wealth is held by Americans, Japanese and Germans, the authors of the report expect the distribution to become more diverse over time as developing countries continue to grow faster than developed ones.