Labor Force Participation Rates for Men and Women, by Age, for Four Labor Force cohorts

This is something I've been thinking about for a while.  But I'm still not sure where it's going or what to say about it.  In any event, the following two charts show labor force participation rates by age groups, for men and women, for four age cohorts.  These are non-overlapping cohorts; the first (C48) consists of people who were just entering the labor force (ages 16-19) in 1948, and were, in 1998, 65-69.  The fourth (C63) is actually my labor force cohort, ages 16-19 in 1963, and now ages 65-69.

(Click to enlarge.)

What is happening is fairly clear.  I'm working on what it means.