A growing number of the Chinese middle class choose to travel abroad. [Photo/IC]

China's emerging middle class has grown into a major force driving the society in a positive direction, according to a report by one of China's top think tanks.

Slightly over half of the population in Beijing and Shanghai fall in the category of "middle class", as does around 40 percent in Guangzhou, according to the research by the Chinese Academy of Social Sciences. The research on the middle class is based on three factors: job category, income and expenditure.

Middle class households in the three cities earn an average income of around 200,000 yuan ($30,000) a year. And more than half have their own property and car.

Findings of the research on China's middle class were compiled in the annual Blue Book of China's Society.

Higher income has led to a positive impact on the quality of life for these people, shows the report, which says China's middle class spend generously on improving their skills and knowledge as well as on education for their offspring.

They also tend to read and travel a lot: people in the middle class travel more than six times within China and two times overseas annually, and read an average of 12 books a year, compared with less than five books for the national average.

Moreover, they show higher enthusiasm for doing good, such as donating blood and taking part in environmental protection activities, and are keen on discussing political and social issues.

The survey also shows a growing sense of identity among the middle class.

According to the survey, close to half of the respondents in Beijing think they belong to the middle class, compared with 30 percent holding the same opinion five years ago, and 66 percent believe they will be part of the middle class five years later.

Another remarkable difference revealed by the survey is that most people in the middle class are employed in private sectors, rather than in public sector as it used to be. And most of them are recruited through personal application, instead of unified assignment by the state.

It is estimated that China has a middle class of around 100 million, and the Chinese government is committed to increasing the population of middle-income earners in an effort to reform the income distribution system and avoid the "middle-income" trap.