China had 340-thousand millionaires in 2009, the fourth highest number in the world in spite of an 11 percent decrease from the year before, according to the 2010 edition of "The Wealth Report" released by Citi Private Bank.

Investible assets of each person in this group, called the High-Net-Worth Individuals (HNWI), total between $1m and $10m, excluding their principal residence.

The survey of global wealth distribution saw a sharp drop in the number of HNWIs as few corners of the world were left untouched by net asset value erosion.

The United States still holds the largest number of HNWIs, standing at 2,519,000, but that figure has dropped 19 percent following the economic downturn.

Next are Japan and Britain, who have 669,000 and 439,000 people included respectively.

Among the world's major economies, India and Portugal saw their number of wealthy people most reduced, by 24 percent each, while Hong Kong, Belgium and Russia saw a reduction of around 20 percent.

Although no economy has seen an increase in the number of millionaires, the report says the fact that asset prices have recovered strongly since mid-2009 means the numbers are expected to recover relatively rapidly.