By the numbers: The best books of the year

This time of year, "Best Books" lists are everywhere.

Every publication seems to have one, and each offers 10, 20 — even 100 — great titles to stack on your nightstand. But when we look at these lists all together, what do they tell us about the state of literature?

We pulled 11 year-end book lists from popular publications and crunched the numbers. What we found: Authors over 50 reign supreme; men still outnumber women; and critics' unique tastes aren't as unique as they think. More from our critical analysis of the critics' choices:

The best of the best

In total, the lists named 162 books as the best of the year.

But great minds think alike: Only 111 unique titles made the cut. Many titles appeared on two, three — even six — "best of" lists. Here are the titles the critics loved most:

• "The Paying Guests" by Sarah Waters - 6 mentions
• "A Brief History of Seven Killings" by Marlon James - 4 mentions
• "All the Light We Cannot See" by Anthony Doerr - 4 mentions
• "The Bone Clocks" by David Mitchell - 4 mentions
• "Being Mortal" by Atul Gawande - 3 mentions
• "Euphoria" by Lily King - 3 mentions
• "Lila" by Marilynne Robinson - 3 mentions
• "The Martian" by Andy Weir - 3 mentions
• "The Sixth Extinction" by Elizabeth Kolbert - 3 mentions
• "Station Eleven" by Emily St. John Mandel - 3 mentions
• "Those Who Leave and Those Who Stay" by Elena Ferrante - 3 mentions
• "An Untamed State" by Roxane Gay - 3 mentions
•"What If? Serious Scientific Answers to Absurd Hypothetical Questions" by Randall Munroe - 3 mentions

The gender gap

Male authors outnumber female authors on the lists this year, but the difference becomes even more pronounced when you break it out by genre. While fiction was nearly an even split, there were twice as many nonfiction books on the lists written by men than by women.

A world view

The authors are predominantly American, which is to be expected: All of the publications we looked at, with the exception of The Guardian, are based in the United States.

While a few English translations made the list, there were no titles from South America or Africa, and only one from Asia.

American authors penned 74 of the acclaimed titles. The United Kingdom produced 21 and Canada 3. Australia, Ireland and Jamaica each had 2, while France, Iraq, Italy, Japan, the Netherlands, Russia and Turkey had 1 title each.

A tale of the ages

What do Jane Austen, F. Scott Fitzgerald, Zadie Smith and Jonathan Safran Foer have in common? They all published award-winning books before the age of 25. The authors who cracked this year's "best of" lists are a decidedly older crew. (Our data excludes the 13 authors coy enough to keep their ages off the Internet.)

The average age of authors on this year's lists is 51. The eldest, John Drury, clocks in at 78; the youngest, Lena Dunham, at 28.

The new kids

Many authors toil in obscurity before their big break. This year, however, seven writers cracked the "best of" lists on their debut books:

• "A Girl is a Half-Formed Thing" by Eimear McBride
• "All Joy and No Fun: The Paradox of Modern Parenthood" by Jennifer Senior
• "Fourth of July Creek" by Smith Henderson
• "The Martian" by Andy Weir
• "The Miniaturist" by Jessie Burton
• "Not That Kind of Girl" by Lena Dunham (While Dunham is hardly emerging from obscurity, this is her first book.)
• "Waiting for the Electricity" by Christina Nichol

The outliers

Each publication compiles its list in a different way, but across them all, fiction and nonfiction dominate. Slate's was the only list to include a poetry title: Claudia Rankine's "Citizen." (Others honored poetry, but on separate "best of" lists). Similarly, only one graphic novel made the lists: Roz Chast's memoir, "Can We Talk About Something More Pleasant?".

Lists and methodology

No two lists are alike. Of the 11 lists we included in our data, some named 10 titles, while others ranked 100. For longer lists, we included only the first 20 ranked titles.

Additionally, some lists split evenly between fiction and nonfiction, while others did not use quotas. To compile the graphs, we used publicly available information about authors; age and nationality was not available for every author.

The Lists

Our analysis included these lists: The A.V. Club, Amazon, Barnes & Noble, Kirkus Review, Library Journal, The New York Times, Publishers Weekly, Slate, The Guardian, The Wall Street Journal and The Washington Post.