With vacation season kicking off this coming Memorial Day weekend, a  new survey reveals nearly 40 percent of American workers leave paid vacation time on the table every year.

The survey by Robert Half International staffing firm confirmed what previous studies have shown --- 500 million vacation days are left unused each year.

Randy McDermott with Robert Half International in South Florida says the company's survey also reveals the top reasons why people don't take their earned days off.

Thirty-eight percent of workers save days in case they need them later, but they end up losing them.

Thirty percent say they fear falling behind at work.

McDermott says employers are more and more encouraging workers to take their vacation time, since many studies show professionals who take vacations and unplug are actually more productive in the long run.






(Photo: Andrew Burton / 2014 Getty Images)