'Call of Duty: Modern Warfare 2' crosses $1bn sales

Gaming company Activision Blizzard has said that sales revenue of its shooter video game has crossed

It launched 'Call of Duty: Modern Warfare 2' last November and has sold about 15 million units so far. About 8 million units were sold out in the first week of its launch that recorded $550m sales.

The second 'Call of Duty' is expected to generate more sales than the first version. In 2007, the 'Call of Duty: Modern Warfare' sold 14.4 million units.