World Audiobook Index: the audiobooks charting most widely today
Every day we add up each audiobook's positions on the Apple Books top 100 in every country we track. Number one is worth 1 point, number 100 is worth 0.01, so a book scores highly by charting near the top in many countries at once.
The index appears after the first nightly update.
How the index works
Chart positions come from Apple Books' public top 100 charts, collected every morning for 35 storefronts. A book's points for the day are the sum of (101 − rank) ÷ 100 across every country where it charts. Each country counts the same, so the index measures how widely a book is read rather than how big a single market is.
Editions sold under a different Apple Books ID, such as a translation, are counted separately, because they are separate products in each store. Author pages bring every edition together.