I really had no idea. The last time I remember seeing it graded was years ago, in a book of book criticism by Vladimir Nabokov, where he gave Miguel only a C minus....
The first link is the above list made available one-book-at-time (with a short description of each), by the "Christian Science Monitor":
click here
This second link below is the same above list at Wikipedia, which shows all of the books on one single page (with links to Wiki articles on specific books). It also includes the names of the 100 authors surveyed in order to compile the list, at the bottom of the page (really quite impressive, with at least two Nobel Prize winners):
