I see that Statistics Canada has just released the results of a study on The Canada–US gap in women's labour market participation, 1997 to 2015.  (Spoiler: The two countries had similar, and rising, rates until about 1976, then Canada's participation rate continued to climb while the US rate began to decline, to the extent that there is now 7-point gap between us on this measure.)

As is often the case, these numbers raise all sorts of questions...