2005 -- 780,000 same sex couples, 390,000 considered themselves spouses
2006 -- 780,000 same sex couples, 390,000 considered themselves spouses
2007 -- 753,618 same sex couples, 341,000 considered themselves spouses
2008 -- 563,743 same sex couples, 150,000 considered themselves spouses
(It appears the numbers for 2005 and 2006 were estimates and now the census is collecting real data.)
1) The percent of same-sex couples who consider their relationship to be akin to marriage has gone down from 50% with the 2005-6 estimates, to 45% in 2007 and now to only 27% in 2009. The comparable number for heterosexual couples, according to the Census Bureau, is 91%. The suggests to me that the same-sex couples are self reporting that their relationships are not "just like" heterosexual couples.
2) The total number of same-sex couples has gone down 28% in a four year period. This suggests that the early estimated numbers were too high or that something has caused a net reduction in the total number of same-sex couples.
Of course, that is not the way the AP article is framed, but those are the actual numbers in the story. The AP story seems to be written focusing on the actual number of gay marriages and civil unions versus the the number who consider their relationships akin to marriage and provides an un-sourced explanation in the fourth paragraph that seems to me to be written to support the "gay rights" talking points:
Analysts said the disparities are probably a reflection of same-sex couples in committed relationships who would get married if they could in their states. The numbers are also an indicator of the count to come in the 2010 census, a tally that could stir a state-by-state fight over same-sex marriage, gay adoption and other legal rights.
But when I look at the numbers, I am thinking that the demand for same-sex marriage in the USA has been significantly overestimated, perhaps to support the cause of "gay rights". Alternatively, it could be that the emphasis on same-sex marriage has caused a significant break-up of gay couples in the USA. If most do not view their relationships as akin to marriage, perhaps the new pressure by one of the partners to marry or form a legal domestic partnership is leading to break-ups.