WASHINGTON (PAI) – The number of unionists nationwide rose by 428,000 in 2008 – the largest rise in numbers since statistics started being kept in 1983 – pushing total union gains among the nation’s workers to almost three-quarters of a million in the last two years, the Labor Department reported Jan. 29.

Union density nationwide also increased, to 12.4% of all workers, from 12.1% in 2007 and 12% in 2006 the Bureau of Labor Statistics added. It called the 2007-2008 increase “statistically significant.”

The labor-backed Economic Policy Institute said with the levels of unemployment declining through 2008, the data “suggests that unions are making a comeback under very difficult circumstances.”

The data cheered union spokesmen.

“The key words this year are ‘statistically significant,'” said Jason Lefkowtiz on Change To Win’s website. “Reported growth for 2007, while encouraging, was small enough that it could have been just statistical ‘noise.’ This year’s results, while not huge, are too big to be outside the margin of error.”

But he warned the first year BLS gathered the data, 1983, saw union density of more than 20%. “We all still have a lot of work ahead of us to rebuild the power of workers in the United States…but every journey starts with a single step forward, and this is definitely one of those,” Lefkowitz said. He predicted passage of the Employee Free Choice Act “would make these first small steps the start of something big indeed.

Added AFL-CIO President John Sweeney: “Today’s numbers confirm what many working people already know: that if given the chance, American workers are choosing to join unions in larger numbers. Workers in unions are much more likely to have health care benefits and a pension than those without a union; in today’s economy, that’s the difference between sinking and swimming.”

While union density rose in 26 states and Washington, D.C., and declined in all but one of the rest, there were some warning signs among the numbers.

The prime one was half the nation’s union members are still in just six states: California (2.74 million), New York (2.03 million), Illinois, (939,000) Pennsylvania (847,000), Michigan (771,000) and Ohio (716,000), in that order. But those states had only one-third of the nation’s workers, BLS said.

Another warning sign is that the union movement is gray: The highest shares of unionization by age were among workers aged 55-64 and 45-54, while the lowest share – 5% – was among workers aged 16-24, who are the new entrants to the workforce.

Several states had big jumps in union density, numbers, or both. One was California, where 266,000 more workers became unionists, and density rose from 16.7% in 2007 to 18.4% last year. Another was Illinois: Union density rose from 14.5% to 16.6% in one year, and the number of unionists increased by 97,000, to 939,000.

Crashing employment in the auto industry appeared in Michigan, where the number of unionists declined by 48,000, to 771,000. Density declined in Michigan from 19.5% in 2007 to 18.8% last year. The total number of Michigan workers dropped by 104,000.

Unionists maintained a huge wage advantage over their non-union colleagues, BLS said. The median weekly wage for union workers last year – the point at which half are above and half below – was $886, up $23 from the year before. For non-unionists, the median was $691, up $28.

Union density increased in a wide range of occupations from 2007 to 2008, even though two key sectors, construction and manufacturing, shed hundreds of thousands of jobs. BLS said there were 1.195 million unionized construction workers last year, or 15.6% of all building tradespeople. That’s up 2,000 from 2007, when union density was 13.9%. In the meantime, construction lost 909,000 workers, many in the predominately nonunion residential sector.