这篇 2007年 Economist 上的文章说圣经每年的销售量高于一亿册。
http://www.economist.com/node/10311317
Yet over 100m copies of the Bible are sold or given away every year. Annual Bible sales in America are worth between $425m and $650m; Gideon's International gives away a Bible every second. The Bible is available all or in part in 2,426 languages, covering 95% of the world's population...
The most prolific producer of Christian missionaries, on a per head basis, is now South Korea.
The biggest Bible publishing houses are in Brazil and South Korea. An interlinked global network of 140 national or regional Bible Societies pools resources to reach its collective goal of putting a Bible in the hands of every man, woman and child on the planet. The American Bible Society, the biggest of the lot, has published more than 50m Bibles in atheist China
准确的估计是困难。但前面那文章说圣经每年都是销售量最大的书籍(并且远远高于任何其它年度畅销书比如说当时的Harry Potter)是没有什么疑问的。