I can't find any evidence from 20th century, but here's a study from 2016: http://ftp.iza.org/dp10179.pdf
It says Americans work 25% more. This is usually the conclusion of this kind of thing.
It says Americans work 25% more. This is usually the conclusion of this kind of thing.
I agree that Americans on average spend more time in work.
More conrroversially, I also think that the notion of work ethics should count in also what you do at work and crunch stories about people sleeping under table should not count as better work ethics. E.g. more hours less effectively is not better work ethics. (That is not to imply American companies are less effective per hour, I don't think that is the case.)