Anyone with an interest in Irish demographic history will like this one:
Sourced from the ESRI Family Figures (2010) report. Well worth a read!
I'm interested in singlehood and couple formation in Ireland, and more specifically, the economic and social factors that mediate it. Ireland has some fairly unique historical rates and patterns in this area - nineteenth century (post-famine) was predominantly characterised by remarkably low marriage rates but with very high fertility rates (observed by Joe Lee: Modernisation of Irish Society; 1848-1918). I'm not familiar with any analysis of this.
Here we see the variability in marriage (inc. common law marriages) rates for the 20th century which shows the increase in family formation through the early and mid twentieth century, up to 1980. Now, it seems marriage rates (people aged 25-35) or singlehood rates are returning to the rates of the Victorian era.
I'd be interested to hear you thoughts on this. I'm working on a theory..