WASHINGTON — Six years after a brutal recession that wiped out more than 8.5 million jobs, Americans are now enjoying a nearly unprecedented level of job security.

The number of people seeking U.S. unemployment aid plunged last week to the lowest in nearly 42 years.

Applications for jobless benefits are a proxy for layoffs, so the low level indicates that employers are keeping their staffs and likely hiring at a steady pace.

Weekly applications for unemployment benefits fell 26,000 to 255,000, the fewest since November 1973, the Labor Department said Thursday. If the data were adjusted for the growth of the U.S. population since then, last week’s figure would likely be an all-time low.

The four-week average, a less volatile number, fell 4,000 to 278,500. The average has fluctuated around that figure since May.

That is a far cry from the depths of the 2008-2009 Great Recession, when more than 600,000 people were applying for jobless aid each week.

One reason for last week’s drop, however, is that auto plants and other factories close briefly in July to prepare for next year’s models. That pushed up applications in the previous two weeks. Now that many factories have reopened, applications have fallen back.

With layoffs down, employers are also hiring more to meet greater demand for their goods and services. The economy added 223,000 jobs in June, and the unemployment rate fell to a seven-year low of 5.3 percent.

The economy has gained nearly 3 million jobs in the past year.