Giant e-tailer Amazon has revealed a fourth quarter 49% uplift in sales to $4.56bn in its international arm, which includes the UK as well as German, Japanese, French and Chinese operations.

In the quarter to December 31, Amazon said excluding the “favourable impact” of changes in foreign exchange rates, international sales grew 37%.

In the same period, group net income increased 71% to $384m, while group net sales increased 42% to $9.52bn, and grew 37% excluding the impact of foreign exchange rate changes.

In 2009, group net income soared 40% to $902m or 29% excluding the impact of foreign exchange rates.

Founder and chief executive Jeff Bezos said: “Millions of people now own Kindles. And Kindle owners read, a lot. When we have both editions, we sell 6 Kindle books for every 10 physical books. This is year-to-date and includes only paid books — free Kindle books would make the number even higher. It’s been an exciting 27 months.”