Americans eligible for paid vacation admitted to using only 51 percent of their eligible time in the past 12 months, possibly costing them more than $1,300. Among employees eligible to take paid time off, 85 percent said they took at least some time off, whereas the rest took no time off. Only one-in-four employees took all their vacation time, according to Glassdoor Q1 2014 Employment Confidence Survey, and a separate survey conducted by research firm Harris Interactive. What's worse is that 61 percent of employees are working while on vacation, despite complaints from family members. About a quarter of employees were contacted by colleagues and one-in-five were contacted by their boss while on vacation. The Center for Economic and Policy Research says most Americans receive ten paid work days a year and six federal holidays. Based on the Labor Department's current average weekly earnings, these employes are losing $1,300 a year by not fully utilizing their vacation time. Many workers averse to taking time off do not realize that this time is already built into their compensation package. The U.S. is one of the few developed countries that doesn't require employers to provide paid time off, yet many companies offer employees these benefits. So, why are employees averse to taking time off? "Fear," says Scott Dobroski, career trends analyst at Glassdoor. "That's the underscoring theme." Twenty-eight percent of employees told Glassdoor that they feared falling behind while on vacation, and 17 percent feared losing their job. Nineteen percent hope not taking leave will give them an edge when it comes to a promotion and 13 percent are just competitive and want to outdo their colleagues. "The inability to disconnect has led to a blurring of personal versus work life," says Piera Palazzolo, senior vice president for marketing at Dale Carnegie Training. "Taking vacation is important for creativity and energy levels," Palazzolo says. "They may be going through the motions at work, but not taking time off can lead to burnout."