North Koreans are much more reserved about sex and marriage than their South Korean counterparts, but men and women on both sides marry at about the same age and are increasingly putting work before marriage, RFA's Korean service reports.
The data suggests priorities and values are shifting in postindustrial South Korean society.
But when you graduate from high school, there is less reason to be secretive.
At this age, couples go on to spend a lot more time together without having to care about about what other people might think.
Strong support for cohabitation is significant, as is a more laissez-faire attitude regarding international marriage.
While the former might be more of a practical concern, the latter corroborates the claim that opinions regarding what constitutes the nation are changing.