While Irish book sales have plummeted, EL James' erotic novel 'Fifty Shades of Grey' is still going strong, selling nearly as many copies in its first four months as 'Harry Potter and the Deathly Hallows' did.

According to the latest figures from Nielsen Bookscan, book sales in Ireland have gone down by more than 11 percent over the past year. However, 'Fifty Shades' has sold about 111,300 copies since it was published in Ireland in April, reports the Irish Independent.

In comparison, 'Harry Potter and the Deathly Hallows,' which was released in July 2007, sold 140,000 copies in Ireland in its first four months.

Alas, the sequels of the 'Fifty Shades' trilogy -- 'Fifty Shades Darker' and 'Fifty Shades Freed' -- have not sold as well as the first novel. Between them, the two sequel have sold only 103,108 copies since they were published last April.

Non-fiction books have had the worst luck in the down market, with 15 percent fewer sales over the last year.

"The economic climate is the likely cause of the decline," said Nielsen Bookscan analyst Russell Bremner.