There's been no real reduction in the number of U.S. school shootings despite increased security put in place after the deadly shooting at Sandy Hook Elementary School in Newtown, Conn., in December 2012, which left 20 children and six educators dead.

An Associated Press analysis finds that there have been at least 11 school shootings this academic year alone, in addition to other cases of gun violence in school parking lots and elsewhere on campus when classes were not in session.

Last August, for example, a gun discharged in a 5-year-old's backpack while students were waiting for the opening bell in the cafeteria at Westside Elementary School in Memphis. No one was hurt.

Experts say the rate of school shootings is statistically unchanged since the mid- to late-1990s, yet the number of school shootings remains troubling.

Ronald Stephens, executive director of the National School Safety Center, said there have been about 500 school-associated violent deaths in the past 20 years.

The numbers don't include a string of recent shootings at colleges and universities. Just last week, a man was shot and critically wounded at the Palm Bay Campus of Eastern Florida State College, according to police. Also this month, shootings occurred at South Carolina State University and Purdue University in Indiana — in both cases a student was killed.

Bill Bond, who was principal at Heath High School in West Paducah in 1997 when a 14-year-old freshman fired on a prayer group, killing three female students and wounding five, sees few differences in how shootings are carried out today. The one consistency, he said, is that the shooters are males confronting hopelessness.

"You see troubled young men who are desperate and they strike out and they don't see that they have any hope," Bond told The Associated Press.

Schools generally are much safer than they were five, 10 or 15 years ago, Stephens said. He noted that perspective is important: In Chicago there were 500 homicides in 2012, about the same number in the nation's 132,000-plus K-12 schools over two decades.

"I believe schools are much safer than they used to be, but clearly they still have a good ways to go," Stephens said.

The recent budget deal in Congress provides $140 million to support safe-school environments, and is a $29 million increase, according to the office of Democratic Sen. Tom Harkin, chairman of the Senate Health, Education, Labor and Pensions Committee.

About 90 percent of districts have tightened security since the shootings at Sandy Hook, estimated Randi Weingarten, the president of the American Federation of Teachers.

Many schools now have elaborate school safety plans and more metal detectors, surveillance cameras and fences. They've taken other steps, too, such as requiring ID badges and dress codes. Similar to fire drills, some schools practice locking down classrooms, among their responses to potential violence.

Weingarten said more emphasis needs to be placed on improving school cultures by ensuring schools have resources for counselors, social workers and after-care programs. Many of these kinds of programs were scaled back during budget cuts of recent years.

Education Secretary Arne Duncan told reporters Thursday that he also believes strong mental health support systems in schools are important. But he said schools are doing a "fantastic" job with school security and often schools are the safest place in a community.