these numbers are across all industries, right? a 40 hour union job has certain parameters such that the work hours aren't going to shift much without larger political shifts within those orgs.
But I suspect the number of hours a non-union knowledge worker works per year has gone up in the same time frame.
Anecdotally, I have swapped stories with my father in law who started his career as a finance worker for a large corporation in the 1980s and he worked significantly more hours than I have at any of my current or previous jobs. 10+ hours 5 days a week was the expectation, plus an hour commute both ways... hard to say if that generalizes in any meaningful way though.
But I suspect the number of hours a non-union knowledge worker works per year has gone up in the same time frame.