The website Flavorwire.com consulted 16 different Best Books of 2012 lists and counted how many times each of book was mentioned to create a Best of Best of 2012 Books List.
According to the this method, the best book of the year is Bringing up the Bodies by Hilary Mantel, it was mentioned in 8 of the 16 lists. There were four books mentioned in seven of the lists. Gone Girl was mentioned in six of the lists. Three books were mentioned five times. Seven books were mentioned four times. Seven books were mentioned three times and 21 books were mentioned twice.
That makes a total of 44 books mentioned at least twice, but 150 books mentioned at least once. The method makes sense, but there are a lot of books. Books are a lot about taste and reviewers have a wide variety of tastes.