Market Research Into Readers

Something I have always wondered is what point-of-view do most readers subconsciously enjoy the most?  How many readers actually pay attention to the words versus the number of readers that just let themselves be swepted away by the writing?

Yes, I know, blah blah blah, just write what you enjoy.  That’s not the point of this post.

What I want to know is do publishers track these statistics?  Do they know that 3rd person perspective novels over 400 pages where the main character is a man will sell twice as much as a 200 page novella about a leprechaun in the 1st person perspective.

I know that there have been basic readability index studies done which shows that a novel written for the grade 5 education level will sell better than any other.