Four Ohio police officers were among the 72 officers who were killed by criminal activity in the United States in 2011, new FBI statistics show.

Last year’s national number of police deaths was the highest since 1995, and the four killings in Ohio were the most in the state since 1997, according to a Dayton Daily News analysis.

The national numbers have risen from 41 in 2008 to 48 in 2009 to 56 in 2010. Of the 72 killings last year, records show 63 of them came by firearms, mostly handguns.

Warren County Sheriff Larry Sims told the newspaper he is concerned about the rising numbers.

“Things are a lot different now,” Sims said. “It appears that people have less concern about taking the life of a police officer. There’s an increasing overall disrespect for laws and authority. It’s scary.”

The deaths in Ohio included sheriff’s Deputy Suzanne Hopper, who was shot to death in a New Year’s Day gunbattle at a trailer park near Springfield in Western Ohio. In March, Sandusky officer Andrew Dunn was shot to death after he stopped a convicted felon riding a bicycle.

The numbers do not include 53 accidental deaths of law enforcement officers in 2011.

From 2002 to 2011, FBI data show 543 law enforcement officers were killed in the line of duty, 500 by firearms, including 366 from handguns. There were 95 deaths from rifles, 38 from shotguns, 35 by vehicles and three from knives or other cutting instruments.

U.S. Attorney General Eric Holder has called the increase in law enforcement deaths “a devastating and unacceptable trend.”

Tom Diaz, senior policy analyst at the nonprofit, nonpartisan Violence Policy Center in Washington, D.C., said the increase of officers killed with firearms is due to multiple factors. He said it’s a natural consequence of the proliferation of firearms, more powerful and affordable semi-automatic weapons and a growing ideology of anti-government sovereign citizens.

Clark County Sheriff Gene Kelly said the increase in officer deaths “shows how violent we have become.”