My guess is 80% read the first couple of words of a headline. The next 15% make it to the end of the headline. 5% actually bother to click through. 4.9% don't get beyond the first paragraph. 0.09% gets to the end. 0.01% actually takes the time to understand what they've read.
Gentlemand, I am quoting you separately because you touched a much wider subject here. The problem with reading these days is very apparent, at least in my country. It wasn't enough that most of the people don't have a capacity or will to read books, most of them being discouraged by the poor education system in which there was a constant obligation to read books not interesting and adequate for a target age, but now we also have a problem of rushed times where "nobody has time for anything" and a constant overflow of information potentiated with the accessibility of technology.....
However, most reads are easy, unsubstantial and people got used to not reading more than two sentences. This also provided ground for click baits and similar news manipulations.
This is of course also reflecting on the problem I mentioned in the OP.