How Many People Have Call of Duty: Black Ops?

How many people have Black Ops?
Call of Duty: Black Ops quickly became the best-selling game of all time, it had sold nearly 14 million copies(as of March 14, 2011.) According to IGN, 1 in 8 households has purchased the game.

2011 STATISTICS
Copies Sold in the United States: 13,700,000


FUN FACTS
When Call of Duty: Black Ops was released, in the first 45 days, the game had already clocked in 600 million hours of play. Stretching this out to years would equal 68 millennium, that's 68,000 years.
HELPFUL LINKS
IGN - Black Ops in 1 of 8 Households in the U.S.
Wikipedia - Call of Duty: Black Ops
Fun Facts Reference - Gamasutra