More than six in 10 workers in a recent Washington Post-Miller Center poll worry that they will lose their jobs to the economy, surpassing concerns in more than a dozen surveys dating to the 1970s. Nearly one in three, 32 percent, say they worry “a lot” about losing their jobs, also a record high, according to the joint survey, which explores Americans’ changing definition of success and their confidence in the country’s future. The Miller Center is a nonpartisan affiliate of the University of Virginia specializing in public policy, presidential scholarship and political history.

Job insecurities have always been higher among low-income Americans, but they typically rose and fell across all levels of the income ladder. Today, workers at the bottom have drifted away, occupying their own island of in­security.

Fifty-four percent of workers making $35,000 or less now worry “a lot” about losing their jobs, compared with 37 percent of ­lower-income workers in 1992 and an identical number in 1975, according to surveys by Time magazine, CNN and Yankelovich, a market research firm. Intense worry is far lower, 29 percent, among workers with incomes between $35,000 and $75,000, and it drops to 17 percent among those with incomes above that level.

Lower-paid workers also worry far more about making ends meet. Fully 85 percent of them fear that their families’ income will not be enough to meet expenses, up 25 points from a 1971 survey asking an identical question. Thirty-two percent say they worry all the time about meeting expenses, a number that has almost tripled since the 1970s.