Even counting the number of hours for which people read doesn't help - some people read slowly, others very fast. And that still doesn't account for the "Herlequin Romance" factor. Does 10 hours reading of "penny dreadfuls" count as much as 10 hours of Anime, 10 hours of Neil Stephenson, 10 hours of Linux Manuals, 10 hours of Shakespeare's Sonnets or 10 hours spent reading the phone book? What about one's comprehension level? Does it count to have read a book and not understood a word of it - or worse, to have read - but completely misunderstood it?

In the end, this comes down to "amount of benefit gained from book reading per year" - and that's almost impossible to quantify.