Curious Google Trends data about the genre

In most cases, actual search data gathered by Google tells us that, year-on-year, the absolute number of people looking for things science fictional is dropping, though more content is being generated! What am I missing?

Caveats:

1. Everything except searches for relatively young authors currently in news & with a significant web presence - Charles Stross, Cory Doctorow, John Scalzi, & Neil Gaiman. And even these are steady rather than growing, except Gaiman who is both growing & outstrips even Doctorow by a factor of 15. And Doctorow's most popular searches have nothing to do with sf; they're mostly about his activism. Authors like Ted Chiang & Mike Resnick have too few searches for Google to bother; Greg Egan is searched for a bit more, but is insignificant compared to Big 4.
2. None of the publishers register on Google's radar - not even Asimov's & F&SF.
   

Major types.

"Horror fiction" has too little volume.

Fiction by size.

There is too little volume of traffic for "flash fiction" & "novelette".

Some big shots.

Adding Arthur Clarke to the list makes the data unreadable because of huge spike for his searches around the time of his death last year. But even he has been showing consistent downward trend.