According to Hewlett and Luce, a survey of the class of 1981 at Stanford University shows that 57% of women graduates leave the workforce.

FORBES: The Immeasurable Value of Retaining Women in the Workplace

Going out, a wide circle of acquaintances - cultural capital and social capital - are key factors in determining your social class, according to the survey.

BBC: Class calculator: A US view of the class system

In a 2007 survey, middle-class Chinese said they belonged to fitness clubs, dined out three times a week and traveled within China twice a year for pleasure.

FORBES: China's Booming Consumer Market

The Tory former chancellor Lord Howe of Aberavon added: "It is well known that the Ordnance Survey is a world-class national mapping organisation and national treasure".

BBC: Peers urge secure future for the Ordnance Survey

Between 2007 and 2010, they spent an extra four minutes during weekdays on educational activities, such as attending class and doing homework, according to the survey.

WSJ: Leisure Tops Learning in Survey

In states like Mississippi, which respondents to ATRA's survey described as particularly hostile to class-action defendants, local business defendants often have a home-field advantage, whereas other states like New Jersey--home to many of the world's largest pharmaceutical companies, and highlighted as a bad place for them to get sued--treat in-state defendants as roughly as out-of-state defendants.

FORBES: The Worst Places To Get Sued In America

Nielsen's survey didn't find a dominant social class on Twitter as much as they found a geographical one: Those who use Twitter are more likely to live in an urban area where there's greater access to wireless network coverage, Mancini said.

CNN: Does class decide online social networks?

Another survey from Wells Fargo found that 30% of middle-class American believe they will need to work until they are at least 80-years-old in order to retire comfortably.

FORBES: The Best And Worst States For Retirement

Among groups leveraging online communities the most, education came in at the top of the class, comprising 11 percent of all social communities, according to the recent Ning survey.

FORBES: Social Media: Evolving From Broadcasting To Conversation

In a survey carried out in 1987, 75% of the population identified themselves as middle class.

ECONOMIST: Business in Japan

The editor of the survey, Phil Baty, said uncertainty in education in England could see world-class universities collapse into global mediocrity.

BBC: Glasgow University