The U.S. workforce is substantially older and better-educated than it was at the end of the 1970s. The typical worker in 2010 was seven years older than in 1979 and over one-third of them had a four-year college degree or more, up from just one-fifth in 1979.

However, the U.S. economy has not managed to translate this substantial upgrading in the quality of the workforce into a similar increase in overall job quality.

Logic might dictate that better-educated workers would generally receive higher pay and better benefits, and that the share of "good jobs" in the economy would have increased in line with improvements in the quality of workforce.

Sadly, the share of "good jobs" in the U.S. economy has actually fallen, according to a new report from the Center for Economic and Policy Research. Over the past 30 years, the U.S. economy has lost about one-third of its capacity to generate good jobs.

The authors, John Schmitt, a senior economist at CEPR, and Janelle Jones, a research assistant, defines a "good job" as one that pays at least $18.50 an hour, has employer-provided health insurance, and an employer-sponsored retirement plan. The $18.50 per hour figure (which translates to about $37,000 per year on a full-time basis) is equal to the inflation-adjusted earnings of the typical male worker in 1979, the first year of data analyzed in the report.

By this definition, less than one-fourth of the workforce in 2010 (the most recent year for which data are available) had a "good job." That's down from 27.4 percent in 1979.

"The standard explanation for this loss of the economy's ability to create good jobs is that most workers skills have not kept up with the pace of technological change," Schmitt said. "But, it is hard to reconcile that view with the fact that even workers with a college degree are less likely to have a good job now than at the end of the 1970s."

The authors suggest, instead, that the decline in the economy's ability to produce good jobs relates to a deterioration of the bargaining power of workers, especially those at the middle and the bottom of the income scale.

According to the authors, the main cause of the loss of bargaining power is the large-scale restructuring of the labor market that began at the end of the 1970s and continues to the present.

The share of private-sector workers who are unionized has fallen from 23 percent in 1979 to less than 8 percent today. Meanwhile, the inflation-adjusted value of the minimum wage today is 15 percent below what it was in 1979.

Expectations for landing a "good" job have been dropping, given that 12.7 million Americans are still unemployed, while another 2.5 million are no longer counted in the workforce.