One of the advantages of being curious is that you're always learning something new and interesting
I just started reading Robert Allen's The British Industrial Revolution in Global Perspective (Cambridge University Press: 2009), and in Chapter 1, I ran across this:
"Northwestern Europe also developed a distinctive pattern of marriage that contributed to high living standards and a broader sphere of personal independence than prevailed in many societies....early-twentieth-century censuses showed two patterns of marriage in the world. East and south of a line from St. Petersburg, virtually all women married, and many of them married in their teens. West and north of that line, as many as one-fifth of women never married, and most who did marry waited until their twenties. These tendencies were most pronounced in northwestern Europe. The first marriage pattern led to high fertility and low living standards. The second...implies a lower level of fertility and one that responded to economic conditions through shifts in the proportion of women marrying and the average age of women at first marriage. [This second] pattern implied a persistently higher standard of living for the mass of the population, and that high standard facilitated savings and economic growth...DeMoor and van Zanden...have traced [this marriage pattern] back England and the Low Countries in the late middle ages. While developments in religious doctrine that emphasized the role of personal (rather than family) choice of marriage partner played a role, the decisive factor was the high wage economy following the Black Death. High wages and the strong demand for labor meant that young people--and young women in particular--could support themselves apart from their parents and control their lives and marriages. Women put off marriage until it suited then, and they found the right partner..."
This is fascinating (to me) and suggests a range of questions about subsequent developments in the economies of the Americas (north and south) and of western and eastern Europe.