While much of the data has already been reported, Pew Research has a very useful analysis of different attitudes in the United States, Europe and the rest of the world on the issue of gay marriage and civil unions. Here are some highlights:
A 2007 Pew Research Center survey found that while a majority of Americans (55%) oppose same-sex marriage, a sizable minority (37%) favor it, figures that have varied only slightly since 2001. A 2006 Pew survey also found that a majority of Americans (54%) favor allowing civil unions, up from 45% in 2003.
A study released by the European Commission in 2006 found that a plurality of people in the European Union (49%) oppose gay marriage. Yet, as in the United States, the public remains divided, with 44% favoring same-sex marriage. Approval rates in individual countries vary greatly. In socially progressive Holland, for instance, 82% of all adults favor allowing same-sex marriage; in heavily Roman Catholic Poland, only 17% of adults support gay marriage.
While public debate in many countries centers on the legal recognition of same-sex unions, in other parts of the world, the question is the acceptability of homosexuality itself. A 2002 Pew Global Attitudes survey found that strong majorities of the people polled in the African and Middle Eastern countries surveyed do not view homosexuality as a socially acceptable way of life. A 2006 report by the Pew Forum on Religion & Public Life similarly found that in the African and Asian nations surveyed, such as Nigeria and South Korea, at least half of the public polled believe homosexuality can never be justified.
Read it all here.
What is interesting from an Anglican point of view is that support for gay marriage in the United Kingdom is only somewhat greater than that in the United States. An additional interesting statistic is that support for gay marriage grew in Canada after it adopted legislation approving gay marriage, suggesting that once civil unions or gay marriage become reality, opposition is reduced over time:
Same-sex couples gained most of the legal benefits of marriage in 1999 when federal and provincial governments extended "common law" marriages to gay and lesbian couples. Through a series of court cases beginning in 2003, same-sex marriage gradually became legal in nine of the country's 13 provinces and territories. In 2005, Parliament passed legislation making same-sex marriage legal nationwide. In 2006 lawmakers defeated an effort by the ruling Conservative Party to reconsider the issue, leaving the law unchanged.
A Canadian Broadcasting Corporation survey conducted three months before Parliament acted in 2005 found that 52% of Canadians opposed the legislation. But one month after passage of the law, 55% favored keeping it on the books. That number stood at 58% in December 2006.
It would be interesting to see how attitudes changed in Vermont and Massachusetts. While I have no data, it appears that the strength of the political opposition to gay marriage is declining in Massachusetts.