National Singles Week was started in Ohio in the 1980s, by the Buckeye Singles Council. Used to recognize single Americans and their contributions, the week is now widely celebrated as Unmarried and Single Americans Week (September 15 - 21 in 2013). The "unmarried" reference is because many people, though not married, don't identify with the term "single" because they are divorced, widowed, have kids, etc.
The United States Census Bureau released statistics regarding Single Americans in July. The numbers come from a variety of credible sources (all of which are cited). For the government, I imagine the purpose of this number-crunching has a lot to do with politics and representation. After all, if I were running for office, I'd want to know how many of my possible votes I might alienate by talking up "traditional family values."
Their study shows that, among other things, there are 103 million adults (people over 18) in the US who are unmarried. 53.6% of those people are women (which just goes to show if you're a single woman, the odds are already not in your favor. Shocking.) Of those 103 million adults, 62% have never been married; 24% were divorced, 14% were widowed.
My purpose in talking about Unmarried Single Americans Week is to reassure myself (and perhaps others) that I am not, in fact, the last single (or unmarried) woman on the planet.
It just feels that way.