Hadn't really thought about that, but I felt like I had tons of homework (in the 1990s). Part of it was not that I had tons of homework, but that my parents instilled in me a desire to not just to the minimum. So stuff took longer because I put more work into it. Even with math, I probably always did a bit more questions than the teacher had assigned. I spent countless hours perfecting essays, writing research reports. Now that I've thought about it, I'd have a tough time believing that kids nowadays get more homework than I did.

So... what I'm saying is, there is the amount assigned, and then there is the amount that kids are actually doing, which are somewhat independent. So it's possible that the assigned amount has increased? or not. It's also possible parents are "better" now (this is true, I think parenting overall has evolved little by little for the better) and are keeping better tabs on their kids, making their kids do more homework, more than just the minimum.

Another data point, I was tutoring some kids in high school math around 2005 or so. There was very little math homework assigned, it was a complete joke, and these kids were going to private school. I remember thinking "what the hell is going on here, what has happened to education!" There was actually some Supreme Court ruling in the province of British Columbia that said that teachers couldn't give homework unless they were going to mark it. Or that they couldn't give "participation marks" for homework, it had to be marked on its merits or not at all. So a lot of teacher's scaled back the assigned homework I think. That's what I heard, I can't find a reference to the court case.