A Gallup poll released on Christmas Eve seems to agree with studies done by the American Religious Identification Survey (ARIS) and reported in previous posts:
The United States remains a dominantly Christian nation. Almost 8 out of 10 Americans identify with a Christian religion. And the vast majority of those who identify with any religion identify with one that is Christian.
Yet, the percentage of Americans who in theory could celebrate Christmas this week as a specific component of their religious faith is down significantly from where it was 50 or 60 years ago. The most important reason for this shift is straightforward: there has been an increasing percentage of Americans who say they have no specific religious identity.
The fact that fewer Americans say they have a religious identity does not necessarily mean there has been a decrease in overall religiosity in America. It is possible that some proportion of those who don't identify with a specific religion are still personally or spiritually religious.
Although a little more than one out of five Americans do not identify with a Christian faith, the Christmas season has ramifications for a broader segment of society. A Gallup survey conducted last year showed that 93% of all American adults said they celebrated Christmas.