Having seen this and reminded myself that I should revisit this and see what changes have happened, I went off to gather some more statistics. Since 2009-05-01 there is no longer any distinction between same- and opposite-sex unions in Sweden, so it is no longer possible to extend these graphs into 2010 as was my intent. However, as the reason for this is greater equality, my idle number-crunching woes pale in comparison.
I briefly toyed with the idea of making the comparison for 2009, but those numbers very much look like artefacts of laws changing half-way through the data set. It also seems as if dissolutions of registered partnerships (the same-sex unions) have not entirely transformed into marriages, at least for statistical purposes (there are registered partnership dissolutions in the statistics for 2010, but naturally no new registrations).In this article, Nate Silver writes that the change in divorce rates in US states that allow or are at least not super-negative to same-sex unions have decreased or at least not increased as much as when compared with highly conservative states.
Following that thesis, I have taken a look at divorce rates in Sweden since same-sex unions (in the form of civil partnerships, originally) were allowed back in 1995. I was initially hoping to find union (and divorce) statistics back to at least a few years before that, but SCB (the Swedish Statistical Bureau) do not have opposite-sex union and divorce stats going back further than 2000. So, unfortunately, I cannot quite do what I had intended, but I can at least look at how same- and opposite-sex union and divorce compare.
We'll need some comparative numbers and based on not very much, the closest we can get is (probably) "unions" divided by "divorces" on a per annum basis.
Bear in mind that there's something subtly odd about these numbers. When "marriages" and "registered partnerships" are tallied separately, at least I would naively expect that "number of men married" would be the same as "number of women married" and "registered partners" be an even number, both in the "male" and "female" category. However, this does not seem to be the case.
There are a couple of possible explanation models, one (the one I currently find most likely) is that they're counting only Swedish citizens, causing a discrepancy as people marry (or partner) someone from abroad.With that in mind, here are some graphs. The value graphed (for each of the categories "women getting married to women", "women getting married to men", "men getting married to men" and "men getting married to women" (denoted, in order, as "female, homo", "female, het", "male, homo" and "male, het") is, for each category, the annual "people getting divorced" divided by "people getting married". This hopefully eliminates all oddities or not around the stats, as long as the "hitched" and "split" numbers are calculated identically.
I have left off the first five years of same-sex partnerships, in the vain hope that any initial "let's get hitched!" excitement leading to a quick divorce has, after that time, stabilised. I don't know if that is the case, as I don't have different-sex marriage data to compare to.
With this in mind, we'd expect that straight people's divorce rates should track pretty close (as, typically, one male and one female are involved in an opposite-sex divorce), but it might still be interesting to compare divorce rates for same-sex couples.
The small difference between male and female numbers may well be that more Swedish men than women marry people from abroad, thus having a slight over-representation in the "married" statistics, while people divorcing may well be more equally Swedish citizens. It is hard to say from just the numbers.
There's also a case to be made that since same-sex unions have been around for a shorter time, it may be that the divorces are yet to happen. This is not something I can contro lfor (but, maybe, worth re-running this data exercise in a few years and see what's happened in the interim).
It may also be that since same-sex unions are comparatively newer and, possibly, seen as "more difficult to enter", that the people ending up in a same-sex union are less prone to splitting. One way of noticing this would be to see how same-sex unions and divorces track over time. Note that for the years 1995-1997, the data files only have ".." as data for same-sex divorces, I don't know if that means "no data available", "zero" or "we're not telling". I have thus been forced to assume that it is 0, for the purposes of the graph below.
If you want the original data, the files I have used are available (opposite- and same-sex)), but bear in mind that these are plain-text files, in Swedish.
This is one of Ingvar's essays