Fewer workers these days are dreaming of a fantastic trip away from the office as more of them are leaving unused vacation days on the table, according to a survey.
"Americans treat vacations as a luxury rather than a right," Expedia said in its analysis of the findings, noting that in the United States, workers with 14 days of vacation took only 10, leaving 4 days unused. A year earlier, they left only two unused, according to the annual survey, released Monday.
The annual Vacation Deprivation study commissioned by Expedia.com and conducted by Harris Interactive was based on the responses of 8,535 employed adults in 24 countries. Respondents who took the full survey were employed, and results were weighted for age, sex, race/ethnicity, education, region and household income.
The percentages varied by region. The French were the least likely to waste vacation. Not only are they likely to use all 30 possible vacation days, they're also the most likely to feel vacation deprived, according to the survey. A full 90 percent of the employed French said they strongly or somewhat agreed with the sentence, "I feel vacation deprived," compared with 83 percent for Italy; 78 percent for Spain; 74 percent for Germany; 49 percent for Ireland; 47 percent for the United Kingdom and Malaysia; 44 percent for Sweden; 41 percent for the Netherlands; 39 percent for Denmark; 38 percent for Mexico; and 17 percent for Norway. (The U.S. percentage was not immediately available.)
(Read more: Travel alert: Frequent flier devaluation)
The decline of the vacation day can be chalked up to the bad economy and rapid changes in the structure of the workforce, said Anat Lechner, a clinical associate professor of management and organizations at New York University's Stern School of Business.
"I think it's pure fear," she said. "And there's a very good reason for that."
The changes in the workforce have made many workers afraid that taking vacation days will make them vulnerable. "Can they do without me?" workers might ask.
Other factors are likely in play, she said. "I'm not sure people can afford to go on vacations," she said referring to the Staycation trend. Whatever the cause, the consequences are not good, Lechner said. People need time to relax, reflect and unwind. An unhappy, fear-driven workforce isn't likely to innovate, she said.
Workers surveyed for the Expedia said there were many reasons they stayed stuck in the office. Many said they were stockpiling days for the future, some said it was too difficult to coordinate time off with family, some planned to cash-out vacation days and others did indeed cite financial worries, workplace insecurity or a mean boss. And 11 percent said work is "their life" and it's hard to get away.
Another study released earlier this year by the Center for Economic and Policy Research noted there is a wide variety within the U.S. when it comes to who gets vacation days at all. "The United States is the only advanced economy in the world that does not guarantee its workers paid vacation," according to the "No-Vacation Nation Revisited" report.
While the average U.S. worker in the private sector gets about 10 paid-vacation days and six paid holidays each year, 23 percent of U.S. workers get no paid vacation at all, according to the No-Vacation Nation report. And while 90 percent of high-wage earners get paid vacation, only 49-percent of low-wage earners get any.
A separate study of small business travel found that some workers are nailing on vacation days whenever possible.
This survey, conducted earlier this fall by Wakefield Research for Best Western International, found that more workers are mixing business with travel. Just over half of the respondents said they are likely to to pay out of pocket to bring a friend or family member on a business trip. Of those surveyed, 46 percent said they are likely to dip into their own pocket to extend a business trip to turn it into a vacation.
(Read more: Baggage claim beer tops off airport income)
—By CNBC's Amy Langfield. Follow her on Twitter at @AmyLangfield.