Summer books: how much have you actually read?

The summer holidays are almost upon us. And cometh the summer, cometh the summer reading lists.

But, as US mathematician Dr Jordan Ellenberg writes in the Wall Street Journal, what about that other crucial literary category: the summer non-read?

He goes on: “[It’s] the book that you pick up, all full of ambition, at the beginning of June and put away, the bookmark now and forever halfway through chapter 1.”

In a bid to find out how much people are actually reading of the books that are on everyone’s lips (we’re looking at you, Piketty), Dr Ellenberg took to Amazon’s “popular highlights” section for a fun, and entirely non-scientific, investigation.

It’s the book that you pick up, all full of ambition, at the beginning of June and put away, the bookmark now and forever halfway through chapter 1. Dr Jordan Ellenberg

For every book’s Kindle page, Amazon lists the five passages most highlighted by readers. Dr Ellenberg reasons that, if every reader is making it to the last page, their highlights will pop up throughout the text. But if people are falling at the first hurdle, the most listed highlights will be at the beginning.

He calls this the “Hawking Index” in tribute to Stephen Hawking’s bestseller, A Brief History of Time – often described as one of the most unread books ever. Here’s how the theory works: take the page numbers of a book’s top five highlights, average them, and divide by the number of pages in the book. The higher the number, the more of the book readers are managing to get through.

So how much of the famous and top-selling books pictured above are people getting through on average? Find out below.

The Goldfinch by Donna Tartt: 98.5 per cent
Catching Fire by Suzanne Collins: 43.4 per cent
The Great Gatsby by F. Scott Fitzgerald: 28.3 per cent
Fifty Shades of Grey by E.L. James: 25.9 per cent
Flash Boys by Michael Lewis: 21.7 per cent
Lean In by Sheryl Sandberg: 12.3 per cent
Thinking Fast and Slow by Daniel Kahneman: 6.8 per cent
A Brief History of Time by Stephen Hawking: 6.6 per cent
Capital in the Twenty-First Century by Thomas Piketty: 2.4 per cent