"Unions and Upward Mobility for Service-Sector Employees," a new report from the Center for Economic and Policy Research (CEPR) shows that nationally, unionization raises service workers' pay 10.1 percent (about $2.00 per hour), compared to non-union service workers, and increases the likelihood that the worker will have health insurance and a pension. Service sector jobs include healthcare and food service workers, housekeepers, janitors and childcare providers.

The vast majority of jobs in this country are now in the service sector, and data from this study demonstrates that service sector workers reap benefits as much from unionization as workers in manufacturing do. In Pennsylvania, for example, more than 77 percent of the workforce is in service-sector jobs, and the unionization rate in those jobs is 14.7 percent. The average wage for unionized workers in the service sector in PA is $19.31, while for non-union members it is $14.27.

The impact of unions in low-wage occupations was even more significant. For workers in the 15 lowest-paying occupations, union membership raised wages by 15.5 percent. The likelihood of having health insurance increased by about 26 percentage points, and the likelihood of having an employer-sponsored pension increased by roughly 23 percentage points.

"Unions give the biggest boost to workers in low-paying occupations because these are the workers that have the least bargaining power in the labor market," said John Schmitt, a Senior Economist at CEPR. "Unionization can turn what would otherwise be low-paying jobs with no benefits into middle-class jobs."

Read the full study here.