Americans are leaving money on the table — in the form of unused vacation time.

Employees who receive paid time off use 51% of it, on average. That's according to a survey run by Harris Poll for the jobs website Glassdoor.

The survey did find some good news: 85% of Americans who receive paid vacation or time off took at least some of it in the past 12 months, and 25% of survey respondents took all their eligible time off.

Taking time off doesn’t always mean vacation, though. Eleven percent of employees said they used time off to interview for another job, while 61% said they did at least some work while they were away from the office.

“It’s clear the word vacation among employers and employees doesn’t mean what it did in the past,” said Glassdoor’s Rusty Rueff. “Before technology allowed us to be connected 24/7, we were more likely to have actually ‘vacated’ our work for a couple of weeks a year, but now, it appears one full day away is a luxury.”

One explanation for why employees don't take the time off they have earned: concern about the security of their job. However, the survey found that confidence in the job market has increased; 44% of employees “believe it is likely they could find a job matched to their experience and compensation in the next six months if they lost their job."

Concerns about layoffs are at their lowest level in five years: Only 15% of surveyed employees reported concerns about being laid off in the next six months, and 23% reported concerns about co-workers being laid off.

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