Analysts have called for more measures to stop the outflow of talents and wealth after a US study claimed that about 22 million people in China want to leave for the US permanently.

The findings by Gallup showed that about 13 percent of the world's adults - or more than 640 million people - say they would like to leave their country permanently.

The US is the most desired destination for worldwide potential emigrants, and about 23 percent of them, or roughly 150 million people, want to move there, including 22 million from China, followed by Nigeria with 15 million and India with 10 million.

According to the Gallup website, the results are based on aggregated telephone and face-to-face interviews with 452,199 people, aged 15 and older, in 151 countries and regions from 2009 to 2011.

The findings have sparked a mixed response from Chinese people, with some skeptical about the data.

"The survey cannot reflect the real picture in China," said He Weiwen, a co-director of the China-US-EU Study Center under the China Association of International Trade, citing the poll's inadequate selection methods.

A staff member surnamed Xue from the Beijing-based Jade Group, which provides immigration services, told the Global Times that most people who immigrate to the US are above 35 years old and have more than 10 million yuan ($1.59 million) in asset.

"They are younger than those who emigrated 10 years ago," Xue said, noting that more senior executives have chosen to immigrate to the US.

Statistics from the US government showed that Chinese immigrant numbers to the country are rising.

In 2011, the world's largest economy, with a per capita GDP of $48,100, granted green cards to more than 1.06 million immigrants. Among them, 87,000 were from China, 16,000 more than in 2010.

According to the Gallup survey, the primary reason for choosing the US is its society's openness to immigrants, followed by other reasons such as opportunities to join family members or to start a new business.

The 2011 China Private Wealth Report, jointly issued by the China Merchants Bank and Bain & Company, a global business consulting firm, stated that China's investment immigrant population was quickly increasing as their overseas assets rise.

In the US, the number of Chinese investment immigrants grew at a compounded annual rate of 73 percent over the past five years, the report said.

About 27 percent of people with more than 100 million yuan in investable assets had completed immigration and 47 percent were considering it.

"The outflow of this group of people will be bad for China. Authorities need to create better conditions for the development of talents and the rich to curb this trend," He Weiwen said, arguing that many immigrants would still largely depend on their homeland.

"Many people who immigrate to the US will find it difficult to integrate with the local community," He Weiwen said. "Some with good educational backgrounds and wealth will find that they can establish their careers there only by devoting themselves to a business related to their home country."

Jin Canrong, an expert on US studies at the Renmin University of China, told China Youth Daily that the US does have advantages in attracting immigrants, but also has many social problems that may pose challenges to newcomers.

"Unfortunately, some media reports in China failed to cover these social problems in the US, resulting in an incomplete image of the US and some people's blind choice of immigrating," Jin said.

Official statistics showed that from late 1970s, when China introduced its reform and opening-up policy, to the end of 2011, the number of Chinese studying abroad was more than 2 million, but only 818,400 of them returned.

The drain of talent has eased slightly in recent years.

Last year, 186,200 overseas Chinese returned, up by 38.08 percent from the previous year, data from the Ministry of Education showed.