Labor unions date back to the 18th century, when the Industrial Revolution brought workers from cottage industries and small forms to transform the world through manufacturing. Workers needed protection in the form of safety standards, limits on work hours and minimum pay. Though union membership is not as strong today as in decades past, unions still represent workers in the global marketplace.

Benefits of Union Membership

Labor unions offer workers support through collective bargaining. Collective bargaining is the banding together of a group of people, such as employees of a company, to enhance their negotiating power. If a single worker demands higher wages or a new safety measure, it can be difficult to get management's attention. However, if all the workers join their voices, there is a much greater chance that a company will hear the demands and feel the pressure to comply.

It's a fact. When labor costs more, employers are more willing to protect their investment in their employees by spending more for training and equipment. When workers receive better treatment, their productivity increases and morale improves. On average, union workers earn 20 percent more than non-union workers doing similar jobs. Union vs. non-union workers are more likely to enjoy benefits such as health care, retirement accounts and paid sick leave.

Pros and Cons of Unions

It depends who you ask. Union workers appreciate the protections and benefits that unions offer. Those who are opposed to unions believe they drive up labor costs and so they're ultimately bad for business.

Top 10 Labor Unions

Here are the top 10 labor unions in the U.S., by membership:

American Federal of State, County and Municipal Employees is the largest public services union in the U.S. Its nearly 1.3 million members include corrections offers, emergency medical technicians (EMTs), nurses and child care providers.

American Federation of Teachers (AFT) is 1.5 million strong. Membership includes teachers of grades pre-K through 12, early childhood educators, paraprofessionals, education-related faculty and staff and government workers in the field of education.

International Association of Machinists and Aerospace Workers (IAM) represents approximately 720,000 workers, including automotive repair workers, truck assemblers and aerospace and fabrication workers.

The International Brotherhood of Electrical Workers (IBEW) has a membership of about 675,000 people in the construction, broadcasting, telecommunications, utilities and railroad industries.

International Brotherhood of Teamsters has about 1.4 million members in 21 industrial divisions, including transportation and construction.

The International Union, United Automobile, Aerospace and Agricultural Implement Workers of America has over a million workers, more than half of whom are retired. More commonly known as the United Autoworkers (UAW), this union not only represents autoworkers but also health care workers, academic student employees and workers in the casino and gaming industry.

National Education Association (NEA) represents over 3 million teachers, including retired teachers and students in teacher training programs.

Service Employees International Union (SEIU) has approximately 1.9 million members, representing over 100 occupations, including maintenance workers, local and state government employers, child care providers, security workers and bus drivers.

United Food and Commercial Workers International Union has 1.3 members who are employed as food processing, supermarket and drugstore workers.

United Steelworkers, with more than 1.2 million members, represents those in the steel, aluminum and metal-working industries. They also represent pharmacy, construction, rubber and chemical plant workers.

How to Get a Union Job

Getting a union job depends on your education, experience and the kind of work you want to do. If you get a job as a teacher, a nurse or a supermarket employee, chances are that a union representative will contact you shortly after you begin work. Joining the union can be as simple as filling out some forms and paying a membership fee (which, depending on the cost, can sometimes be arranged through payroll deductions).

Union jobs in the construction, manufacturing and transportation sectors often require an apprenticeship, which you secure by applying, just as you would for any job. In an apprenticeship, you attend classes and get on-the-job training for a period of time, typically between two and five years, before becoming a journeymen.

If you're interested in a union job, contact someone at a local union office. They can provide you with the information necessary to get the education, training and professional network you'll need to get a union job and join a workers' union.