“These numbers also speak to the fact that there is demand among the public for unionization,” said Ben Zipperer, a research associate with the Center for Economic and Policy Research in Washington.

The Bureau of Labor Statistics reported Wednesday, January 28, that union membership increased by nearly half a million members in the past year to 16.1 million workers. Unionized workers now represent 12.4 percent of the workforce, up from 12.1 percent a year earlier.

The increase in union membership represents a sustained turnaround for unions, which had suffered continual losses since the Labor Department began gathering annual union membership rates in 1983, when 20.1 percent of the workforce was unionized.

Unions, though, struggled to increase their membership among private-sector workers, a major reason the Employee Free Choice Act, which applies only to private-sector employers, has become so strategically important to the future of unions.

Private-sector workers were nearly five times less likely than public-sector workers to be in a union.

The Labor Department also reported mass-layoff figures on Wednesday. In 2008, mass layoffs—defined as a single employer cutting 50 or more jobs at one time—rose to their highest level since the recession following the September 11, 2001, terrorist attacks. Mass-layoff events numbered 21,137, the highest figure since 2001, leading to jobless claims of about 2.1 million, the highest since 2002.

On Monday, January 26, employers worldwide announced mass layoffs totaling about 70,000 job losses at such companies as ING, Sprint Nextel and Pfizer. In 2008, mass layoffs hit manufacturing employers hardest, according to BLS statistics.

“We’re clearly in a steep recession with no bottom in sight,” said James Parrot, deputy director and chief economist of the Fiscal Policy Institute in New York. “The mass layoffs are just a ripple on the ocean of bad news.”

Concerns about layoffs and reduction in benefits could help unionization efforts.

“One of the major reasons for joining a union is that they do help bring health care benefits to employees, especially to low-wage workers,” Zipperer said.

Low-wage workers are less likely to have health care benefits, especially if they work for small employers, according to a paper by the Kaiser Family Foundation published in October.

In a study published by the Center for Economic and Policy Research, unionized female workers were about 19 percentage points more likely than nonunion women to have employer-provided health insurance and about 25 percentage points more likely to have an employer-provided pension.

Workers in education, training and library occupations had the highest unionization rate at 38.7 percent. Among states, New York had the highest union membership rate at 24.9 percent, while North Carolina had the lowest rate, 3.5 percent.