Just this year, at least 14 school shootings have occurred in the U.S. By March 8, this totaled to an average of 1.5 shootings per week according to CNN.

Compared to other developed countries, the U.S. has an unusually high rate of gun violence. According to the U.S. Center for Disease Control and Prevention, 31,076 deaths occurred in 2010 as a result of gun violence. Data from the United Nations also depicts that the U.S. has six times as many firearm homicides as Canada and Germany.

The main cause of the higher rate of gun violence in the U.S. is that there are more guns in circulation. According to Vox, America is 4.4 percent of the global population, but houses half of all civilian-owned firearms in the world.

Extensive reviews from Harvard School of Public Health Injury Control Research Center show that across high income countries, having more guns in circulation leads to higher rates of gun violence. In England, for example, the enactment of firearm regulations lowered gun-related homicide rates.

“We refused over the years to really reduce the amount of guns in this country,” said Will Pizio, professor of justice and policy studies. “In England, they banned guns. 90 percent of the police officers don’t carry guns, man. A couple years ago, there were 15 gun murders in London, a city of 8 million people.”

This trend also appears within the U.S., since states with more guns have higher rates of homicide.

While federal law requires licensed firearms dealers to conduct background checks, unlicensed dealers bear no such restrictions. According to the Giffords Law Center, 42 percent of U.S. gun owners acquired their most recent firearm without a background check. Other countries that require background checks see lower rates of firearms violence.

“There are a series of firearms legislation going on in the UK, and after eight years of campaign, they actually put in place strict firearms regulation,” said Ziwei Qi, visiting instructor for justice and policy studies. “So they have very scrutinized, restricted and rigorous background checks before any buyers want to purchase guns. And also, just like alcohol, they’re preventing any young people under 21 years old from purchasing those high capacity ammunition magazines in order to protect the public.”

Some opponents of firearm regulation argue that other factors such as mental illness are more responsible for gun violence than gun ownership. Many psychologists, however, argue that the variation in mental health is not enough to account for the difference in gun deaths.

“I don’t assume that young people are more isolated in America than they are in Germany or France or Italy, or any other real issue is not people being isolated,” said Dana Professor of Psychology Richie Zweigenhaft. “The real issue is people having access to weapons.”

Despite the U.S.’ longstanding gun culture, some regulations are very popular. According to the Pew Research Center, 84 percent of Americans support background checks for private sales and gun shows, and 89 percent of all Americans support banning the sale of guns to those with certain mental illnesses. Special interest groups, such as the NRA, often donate money to politicians to prevent these regulations from being passed.

“The NRA has contributed so much money, and some other real conservative individuals and organizations contribute so much money too. Many politicians are afraid to go against those organizations because they’re afraid they’ll lose their support.” said Zweigenhaft. “Our democracy isn’t working effectively because of money in our electoral process.”

Qi echoed this sentiment.

“When you see that once politics and money (mix) with action and political affiliation, that really makes it hard to let Congress or the Senate to pass any legislations,” said Qi. “I think definitely the money and the politics, they become friends.”