JPM | Image Source | Getty Images

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.

(Read more: Millennials traveling for business? Room service, please)

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.

Unused vacation days Country Vaction days received Vacation days taken France 30 30 Denmark 30 29 Spain 30 26 Italy 28 20 United States 14 10 Malaysia 12 10 Thailand 11 8 Japan 18 7 South Korea 10 7

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.