In the late 1940s, the labor participation rate for men was nearly 87%. For every 100 men working, there were only 37 women.
By last month, after declining for 7 decades, the labor participation rate for men was 69.3%. Now, for every 100 men working there are 82 women working.
You can see that in this graph. The blue bar - men's participation rate - slowly falls over time. Meanwhile, until about the start of this century, women were gaining on men.
Curiously, women's participation rate as a percentage of men's has seemed to level off at about 80%. It hasn't moved much since the turn of the century and it seems plausible that it won't ever catch men's rate of labor participation.
So that raises a question. Has the steady decline of men's labor participation rate been because of women entering the labor force or do we simply need fewer workers as a percentage of the population? Will women's participation rate as a percentage of men's stabilize and if so, will their rates of participation join men's in slow, gradual decline? Will households - and not just men - need to work less in the future?
I don't know enough about why men's rate of labor participation has fallen so steadily for nearly 70 years to say. I do think it's a remarkably steady fall and it might just be a leading indicator of labor participation rates for men and women.
Now we need another line that shows robots' labor participation rate. Because maybe - just maybe - that rate will climb as women join men in gradual liberation from work.