The proportion of Americans who say a religious day of rest is personally important to them has dropped to 50%, reflecting growing secularism over recent decades, according to a new poll.



A similar question asked in a 1978 survey showed 74% of respondents saying the Sabbath had personal religious significance.



The new poll also showed a big fall in those saying they attended weekly religious services, from 55% in 1978 to 27% now. Jews were least likely to attend services and Mormons were most likely.



The survey was carried out by YouGov on behalf of the Deseret News, a “family-oriented” news site based in Salt Lake City. It questioned 1,000 Americans across religious, racial, gender and age groups.



The poll found that more than six in 10 Americans agreed that it was important for society to have a day of the week set aside for spiritual rest. YouGov adjusted the day depending on the respondent’s religious affiliation: Sunday for Christians, Saturday for Jews and Friday for Muslims.



Young Americans – the so-called millennial generation – are the least likely to consider the Sabbath to have religious or spiritual meaning: 41% of those born in the run-up to the millennium said it was personally significant, compared to 58% of those born before 1945.



Mormons, black Protestants and evangelical Protestants were most likely to agree on the importance of the Sabbath, and Jews and the religiously unaffiliated least likely. The views of Muslims, who make up about 1% of the US population, were not recorded.



Respondents who said they worked in a full- or part-time job on the Sabbath totalled 13%, although the figure rose to 18% for millennials. Almost one in five people said they went shopping, and 23% took part in sports or outdoor activities. For 63%, the Sabbath was a day of rest and relaxation.



Mormons were more likely than any other to attend religious services, with 69% saying they went to church. Just over half of people identifying as black Protestants went to church, and only 5% of Jews said they attended synagogue on the Sabbath. The national average for attending weekly religious services was 27%, according to the poll.



More than half the respondents (55%) agreed that public and private organisations should accommodate people who wish to observe the Sabbath even if it inconvenienced the organisation.



The overall picture reflects a decline in religious activity and belief among the American population. Last year, the highly respected Pew Forum published data showing that almost 23% of Americans defined themselves as religiously unaffiliated, up from 16.1% in 2007.



About 70% said they were Christian. But Pew also reported that only 30% of Christians have “high” involvement in their congregations, including attending religious services at least weekly.

