substantial increase
and the other comments in both articles. I find them hard to understand, what is a substantial increase?
I just like to see numbers and graphs, then again it could be a very subjective analysis anyway - trying to judge people's reading skills probably over many different methods of monitoring is always going to produce a large margin for error. Essentially what I'm wondering if everything is actually always been about the same and the errors in the measures are large enough to show you that.