Amazon said 'Harry Potter and the Deathly Hallows' was the company's largest new product release ever.
It said its global pre-order sales total was 2.2 million - a 47% increase on its previous record which was for 'Harry Potter and the Half-Blood Prince'.
The online retailer was selling one copy of the final instalment every four seconds when pre-orders peaked, it said.Harry Potter and the Deathly Hallows (Book 7)
