An old security guard stands at a gate of a residential community. (File photo)

Who are the security guards working day and night in China's residential communities? A recent survey by Shanghai-based Labor Daily shows that men comprise 100 percent of them, and that they are often advanced in age and not well educated.

Guards are usually employed by property management companies to undertake a broad range of tasks, such as securing gates, patrolling, registering visitors, and facilitating car parking.

The survey says 51 percent of the guards have a monthly salary of 2,000-3,000 yuan ($322-483), 31 percent receive 3,100-4,000 yuan, and the average income of shanghai guards is 2,600 yuan.

There are also four percent of employees earning less than 2,000 yuan, despite the city's minimum wage being set at 2,020 yuan per month.

As well the relatively low income, only 26 percent of respondents had their social security rights, which include five different types of insurance plus one mandatory housing fund, fully guaranteed.

The group barely receives any bonuses beyond the state-required allowance during the hottest days.

The survey shows only men take the profession. Forty percent are aged 51-60 years old and 29 percent are between 31 and 40. Those aged between 41 and 50 account for 12 percent.

Fifty-two percent have a high school education background, and 44 percent have finished junior middle school. Only four percent have gone to college.

Fifteen percent have more than 10 years working experience before taking the job, 18 percent have worked one or two years, and 33 percent have three to five years of working experience.

In terms of career prospects, 26 percent see no promising future, contributing to a high job-hopping rate in the profession.

However, a security guard manager says that employees are not expected to work for a long time, because they may get too familiar with residents in a community and become "poachers." Collecting parking fees, for example, is a potential source of gray income, worth hundreds of yuan per season.

China has 4.5 million security guards and about 4,200 security service companies, a recent report showed.