At some other federal regulatory agencies, a much higher proportion of employees are involved in enforcement activities, the investigators found.
The proportion of employees in privately provided services rose from 5% in 1993 to 23% in 2011.
The proportion of employees on less than the living wage is 22%, up from 21% last year, says the study.
EMPLOYMENT The proportion of employees who work part-time has risen in most OECD countries during the 1990s.
Despite a challenging economic environment, the Guardian has bucked a national trend that has seen a fall in charitable giving and the proportion of employees that are volunteering.
The proportion of employees on less than the living wage is now 22%, up from 21% last year, the study found.
As a result, some companies are trying to make sure the proportion of employees who are recommended doesn't get too high even as they expand their referral programs.
About one-tenth of the workforce is formally organized, but the proportion of employees who maintain membership in a labour union is much higher.
Black customers at Spanish fashion retailer Zara's New York stores have been disproportionately identified as potential thieves, a significant proportion of employees surveyed by the Center for Popular Democracy have claimed in a new report released on Monday.
The proportion of employees saving money into a workplace pension scheme is at its highest level for 17 years, driven by a huge increase in the number of people in their 20s saving for retirement.
CNBC Bankers Brace for 'Doughnuts' | In London, bankers are dreading a round of zero bonuses, known as doughnuts, which could hit a larger proportion of employees than in the 2008 crisis, Reuters reports.
