Sausalito, Calif. (CBS SACRAMENTO) — The average American employee who receives vacation or paid time off only used about half (51 percent) of this eligible time off in the past 12 months, and many can’t stop working even while they are away on vacation, according to a new survey released by Glassdoor.

The business-insider company “Employment Confidence Survey” found for the first quarter of 2014 that more than one-in-five employees (22 percent) reported that they received no vacation or paid time off. Only 25 percent of employees with paid time off took all of their vacation days in the past year.

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For employees who do receive vacation or paid time off, 85 percent of survey respondents said they have taken at least “some time off” in the past 12 months. Fifteen percent reported taking “no time off” in the past year, and on average, employees took only about half (51 percent) of their eligible time off in the past 12 months.

And many Americans were not able to put their work aside even when they were on vacation.

Of the employees who take any of their vacation or paid time off, 61 percent report doing some work while on vacation. One-in-10 employees said they used vacation time to interview for another job, and one-in-five (20 percent) of employees ages 18-34 said they used their vacation time to interview elsewhere.

Fears of Great Recession layoffs and being unable to find another job added to the issue that the U.S. is the lone industrialized country that doesn’t guarantee paid days off from work.

“Fear is still motivating people to not be away from the workplace,” even though concerns about layoffs have mitigated since the recession, Rusty Rueff, a career and workplace expert at employment site Glassdoor, told CBS Moneywatch. “There’s a lot of motivation that says, ‘I’m afraid of being away for too long.’”

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The ubiquitous presence of portable technology in workplaces– including laptops and smartphones — also makes it easier for employees to work even when they are away from the office.

“Couple that with how technology works, and 61 percent of people who take time off are working during vacation. You are seeing the American worker say, ‘I may be out of the office, but work is really, really important,'” Rueff told CBS Moneywatch.

One-third of the employees surveyed reported that they work on vacation because “no one else at my company can do the work,” and 28 percent said they have a “fear of getting behind.”

Twenty-two percent said it’s due to their “complete dedication to the company.”

But despite Americans’ employment concerns, they’re also more confident and optimistic about their role in the workplace.

About 44 percent of employees surveyed said they expect a raise over the course of the next year, which Glassdoor reports as an all-time high since starting the employment survey in 2008. Men, at 49 percent, were more likely than women, at 38 percent, to expect a raise.

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— Benjamin Fearnow