The big assumption here is that most people use the space bar to jump one page at a time while reading. For me, I typically scroll through the page a little at

The big assumption here is that most people use the space bar to jump one page at a time while reading. For me, I typically scroll through the page a little at a time and follow along while I read. I'd be curious to know which approach is most common. I guess it wouldn't actually be that hard to collect.