About 35 percent of U.S. workers say they won't use all their time off this year. In fact, 18 percent plan to work the entire holiday week and 81 percent of them say them expect to be at least somewhat productive.

Of those taking time off, 64 percent say they will check in with the office, according to pollsters from Robert Half.

About 21 percent of those who aren't taking vacation say they just have too much work to do, and 15 percent say they have no money to pay for a vacation. About 3 percent said their bosses discourage taking time off, and about 9 percent feel guilty taking time off.

Not all those who don't take vacation will lose it. About 43 percent said they'll save it for later.

Not everybody is sticking at the office. Eighty percent of New Yorkers told pollsters they would use all their vacation days.