The benefits of a strong job market are spreading in the form of higher wages for many of those left behind for much of the past decade’s economic expansion, including young Americans, low-income households and people with the least education.

The unemployment rate in September fell to 3.7%, its lowest level since 1969. That is creating worker shortages and wage gains, not just for high-skilled workers who tend to command the best pay but also for low-skilled and blue-collar workers whose wages lag behind.

A study by The Conference Board this week showed shortages are now most acute in blue-collar and low-pay service occupations, in part because of slow labor-force growth among those without college degrees. It found wages in blue-collar industries, such as construction and maintenance, have risen more in recent quarters than wages in white-collar management jobs.

Pay in the retail sector, for example, rose 3.8% in the second quarter, more than the 3% increase for professional-services workers, according to the Labor Department.

“You have more and more demand for blue-collar service workers, but the number of people interested in those jobs are shrinking,” said Gad Levanon, one of the authors of the report.