Gov. Martin O'Malley is set to sign into law some of the toughest gun restrictions in the nation on Thursday at a time when gun deaths in Maryland are at their lowest point since the FBI started collecting data in 1995.

In Maryland, 272 people were killed with a gun in 2011, the most recent year the FBI data is available, down 34 percent from 414 firearms homicides in 2007.

The new law would outlaw the sale of 45 assault rifles, require licensing and fingerprinting for new handgun purchases, restrict ammunition magazines to 10 rounds and outlaw gun ownership by the mentally ill. It would become effective Oct. 1.

Gun deaths
Year Maryland D.C.* Virginia
2011 272 77 208
2010 293 99 250
2009 305 113 229
2008 353 NA 240
2007 414 NA 287
2006 403 NA 264
2005 418 NA 318
2004 386 NA 270
2003 370 NA 280
2002 301 NA 257
2001 293 NA 226
2000 296 NA 251
1999 293 NA 243
1998 331 NA 278
1997 389 242 346
1996 424 NA 322
1995 433 269 351
*Data was not reported by D.C. in years listed NA. Data reporting is not mandatory.
Source: FBI Uniform Crime Report

Critics and pro-gun groups say the law is unnecessary as gun deaths continue to fall.

"We would argue that we've actually been safer since, for example, the [federal] semi-auto [assault rifle] ban expired in 2004," said Erich Pratt, spokesman for Gun Owners of America. "What that means is the very guns that were banned are legal, out on the streets, and there are fewer murders. We're safer."

Gun deaths are down nationally too, as homicides in general have dropped. A report released last week by the federal Bureau of Justice Statistics showed that shooting homicides fell 39 percent, from a high of 18,253 in 1993 to 11,101 in 2011. Those figures are matched by a Pew Research Center study that shows that gun homicides per 100,000 people declined from 7 in 1993 to 3.6 in 2010.

However, groups advocating for stricter gun control say the decline in gun killings shows that stricter gun laws are working.

O'Malley's "law is very necessary because too many people die every year because of gun deaths. The fact that states that have gun laws like that, they see gun deaths fall," said Vincent DeMarco, president of Marylanders to Prevent Gun Violence. "There are hundreds of Marylanders who die every year because of guns, and that doesn't need to happen."

DeMarco said it's no coincidence that gun homicides began to fall from their peak in 1993 -- the same year Congress passed the so-called Brady Law requiring background checks for all gun purchases from federally licensed firearms dealers.

However, strict gun laws aren't always an indicator of how high or low firearm homicide rates will be.

The Law Center to Prevent Gun Violence gave Maryland a "B" grade in 2012 for having strict gun regulations. Virginia got a "D". Gun deaths have fallen in both states, though Virginia has historically had fewer gun homicides than its neighbor to the north.

In Virginia, 208 people were killed with a gun in 2011, down from a historic high of 346 in 1997. Virginia law doesn't include some of the restrictions Maryland does or will under the new law, such as licensing for handgun purchases, handgun registration and a ban on assault weapons. Virginia in 2012 repealed its last major restriction on gun ownership: a law restricting Virginians to one handgun purchase a month.

The District also restricts gun ownership through an assault rifle ban, permit requirements for handgun sales, a 10-round limit on ammunition magazines and a prohibition on concealed or open carry. D.C. saw 77 gun homicides in 2011, down from a high of 332 in 1995.

The National Rifle Association plans to file a lawsuit challenging Maryland's new law once it is signed. The NRA declined to comment until the suit is filed.