A survey by Harris Interactive, Inc., found that by the end of 2012 Americans will leave an average of 9.2 vacation days unused, up from 6.2 days in 2011.

According to a survey by Expedia, here are the top five reasons why U.S. employees don’t use all of their vacation time:

I can’t afford a vacation;
My work is my life;
I have trouble scheduling far enough in advance;
I can get paid for my unused vacation days; and
Taking off might be perceived negatively at work.

Unfortunately, only the Japanese take fewer annual vacation days than Americans (5 versus 12), compared to 20 in India, 25 in the UK, 28, in Germany, and 30 in Brazil. Although employers want employees to work hard, burnout and disengagement is a real concern. If it were my company, I would make sure my employees used all their vacation!