Riding high on strong economic growth and robust gains in stock markets, the number of millionaires in India has crossed the 1 lakh mark - emerging as the world's second fastest growing nation after Singapore.The number of high networth individuals (HNIs), with a net assets of at least $1 million, increased 20.5% to 1,00,015 in last year, second only to 21.2% growth in Singapore, according to the World Wealth Report released by Merrill Lynch and Cap Gemini today.The number of Indian millionaires stood at about 83,000 in 2005.Besides India, countries like Australia, Brazil, Canada, China, Germany, Russia, UK and the United States also have more than 1 lakh people with at least $1 million in their kitty, excluding their primary residence and consumables.Worldwide population of HNIs has increased by 8.3% to 9.5 million, while their collective wealth rose by 11.4% to $37.2 trillion in 2006, the report says.While attributing the wealth generation to gains in gross domestic product, and continued market capitalisation growth across the world, Merrill Lynch and Capgemini predicted overall HNI financial wealth to grow to $51.6 trillion by 2011 at an annual rate of 6.8%.Driven by strong gains in countries like India, Singapore and China, the combined HNI wealth in Asia increased 10.5% to $8.4 trillion."Asia is also home to some of the fastest growing markets in terms of HNI population, occupying five out of the top 10 spots globally," the report said.