The year

began to develop the AR-15 (AR meaning "ArmaLite," not "assault rifle").

1959: The first year the AR-15 was manufactured by Colt. 

M-16: The automatic infantry rifle design based on the AR-15. 

4,299,551: Guns manufactured in or imported to the U.S. in 2001.

9,162,924: Guns manufactured in or imported to the U.S. in 2009.

50: States in which AR-15-style rifles are legal.

2.5 million: AR-style rifles sold between 1986 and 2010, according to National Rifle Association reports.

30: Percentage of AR-15 owners who purchased their first rifle in 2009 or 2010.

519: AR-15 models on the commercial market in 2011.

12,626: Deaths by firearms in the U.S. last year.

323: Deaths by rifles that year.

28: People killed in shooting sprees last week in the U.S. with AR-15-style rifles. 

30: Most rounds that can be held in a standard magazine. Larger magazines can hold up to 100 rounds.

10: Most rounds a magazine may legally hold under gun-control legislation proposed by state Sen. Ginny Burdick (D-Portland). 

0: Restrictions on semiautomatic rifles in Oregon. 

30: Minutes in which Oregon State Police must complete a background check on a person buying a gun—or provide an estimate of how much longer it will take.

$10: Fee for that background check. A buyer must provide full name, address and an Oregon driver's license.

60: Percentage of AR-15 owners who own more than one of the rifles.

35: Percentage of AR-15 owners who first owned a paintball gun.

44: Percentage of AR-15 owners who have military or law enforcement backgrounds.

$1,083: Average price, with accessories, of AR-15s purchased new in retail stores.

$436: Average amount an AR-15 owner spends on after-market accessories.

8/10: Proportion of AR-15 owners who say they weren't able to fire their guns as much as they would have liked in the past year.

7,000: Gun manufacturers that are members of the National Shooting Sports Foundation, a gun lobbying group and defender of the AR-15.

06470: ZIP code of the National Shooting Sports Foundation, based in Newtown, Conn.

2.7: Distance in miles from the National Shooting Sports Foundation's headquarters to Sandy Hook Elementary School.

SOURCES: FBI; U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives; National Rifle Association; National Shooting Sports Foundation; Shooter's Bible Guide to AR-15s; Google Maps