(Reuters) - Nine in 10 Americans say they celebrate Christmas - including 80 percent of non-Christians, according to a poll in the United States released on Wednesday.

But only half of Americans view Christmas mostly as a religious holiday, while a third view it as more of a cultural holiday, according to the poll by the Pew Research Center. Others said it was both, or gave no opinion.

The poll looked both at how Americans celebrate the season now, and how they celebrated when they were children. Some Christmas traditions have stayed the same for people over the years, while others have faded.

For example, 86 percent said they would attend a gathering with family or friends on Christmas Eve or Christmas Day, down slightly from 91 percent who said they did this as children. About 86 percent planned to exchange gifts, a slight drop from the 89 percent who said they did so as children.

Traditions that have fallen off for some respondents include sending holiday or Christmas cards, going caroling and attending religious services.

Slightly over half, or 54 percent of Americans, said they plan to attend Christmas services this year, compared with 69 percent who said they did it as children. That's compared with 36 percent who say they go to church in a typical week.

Younger adults were the least likely to see Christmas as a religious holiday, at 39 percent, compared with 66 percent of those aged 65 or older, according to the poll.

Younger adults interviewed were also somewhat less likely to believe in the virgin birth. A total of 66 percent of adults between 18 and 29 believe that Jesus was miraculously begotten by God, compared with 76 percent of all other adults, the poll found.

When asked what they most looked forward to about Christmas and the holidays, the vast majority, at 69 percent, said spending time with family and friends. Asked what they liked least, one-third cited commercialism, while 22 percent said the season was too expensive.

The survey interviewed 2,001 U.S. adults between Dec. 3 and 8, by landline and cell phone. The margin of error was plus or minus 2.6 percentage points.

(Reporting by Mary Wisniewski in Chicago; Editing by Sharon Bernstein and Lisa Shumaker)