Last week, a shooter at Saugus High School in Santa Clarita, California, killed two people and injured three others. Over the weekend, a shooter at a party in Fresno, California, killed four and wounded six more. Today, a shooting outside a Walmart in Duncan, Oklahoma, reportedly killed three people — including, potentially, the gunman.

It’s moments like these that can make it seem as though America is going through a momentary spike in gun violence, even above the usual rates. But this level of shootings is, in reality, pretty typical for the US.

According to the Gun Violence Archive, there have been more than 370 mass shootings in the US so far in 2019, with mass shooting defined as any incident in which four or more people, not including the shooter, were shot but not necessarily killed. That’s an average of about eight mass shootings a week.

That’s still only a fraction of all US gun deaths, with mass shootings responsible for less than 2 percent of gun deaths in America in a typical year. In 2017, there were nearly 40,000 gun deaths, an average of almost 109 gun deaths a day and more than four an hour. Around 60 percent of those gun deaths are suicides.

This really is America.

Although this is typical for the US, it’s nowhere close to normal in the rest of the developed world. A 2018 study in JAMA found that the US’s civilian gun-death rate is nearly four times that of Switzerland, five times that of Canada, 35 times that of the UK, and 53 times that of Japan. There are, on average, more than 100 gun deaths in the US every day.

In many ways, Americans are desensitized to this. Last week, a gunman in San Diego killed his estranged wife and three of his children. That shooting drew little national attention, especially compared with the Saugus High School shooting. In contrast, a similar murder-suicide in 2018 in Osmington, Australia, drew international attention because it was so rare.

Why is this the case in the US? It’s the guns. No other country in the world has as many guns as America, and other developed countries have significantly stricter gun laws. That’s the issue.

America’s gun problem, briefly explained

It comes down to two basic problems.

First, America has uniquely weak gun laws. Other developed nations require one or more background checks (at the very least) to purchase a gun, and almost always something more rigorous beyond that, from specific training courses to rules for locking up firearms to more arduous licensing requirements to specific justifications, besides self-defense, for wanting to own a firearm.

In the US, even a background check isn’t an absolute requirement; current federal law is riddled with loopholes and hampered by poor enforcement, so there are many ways around even basic background checks. And if a state enacts measures that are stricter than federal laws, someone can simply cross state lines to buy guns in a jurisdiction with looser rules. There are simply very few barriers, if any, to getting a gun in the US.

Second, the US has a ton of guns. It has far more than not only other developed nations but also any other country, period. In 2017, the estimated number of civilian-owned firearms in the US was 120.5 guns per 100 residents, meaning there were more firearms than people. The world’s second-ranked country was Yemen — a quasi-failed state torn by civil war — where there were 52.8 guns per 100 residents, according to an analysis from the Small Arms Survey.

Both of these factors combined make it uniquely easy for someone with violent intent to find a firearm, allowing them to carry out a horrific shooting.

This is borne out in the statistics, which show that America has far more gun violence than other developed nations. The US has nearly six times as many gun homicides as Canada, more than seven times that of Sweden, and nearly 16 times that of Germany, according to UN data for 2012 compiled by the Guardian. (These gun deaths are one reason America has a much higher homicide rate, which includes non-gun deaths, than the rest of the developed world.)

If having so many guns around actually made the US safer, as the National Rifle Association and pro-gun politicians claim, America would have one of the lowest rates of gun violence in the world. But the statistics suggest that, in fact, the opposite is true.

The research, compiled by the Harvard School of Public Health’s Injury Control Research Center, is also pretty clear: After controlling for variables such as socioeconomic factors and other crime, places with more guns have more gun deaths. Researchers have found this to be true not only with homicides but also with suicides (which, in recent years, comprised around 60 percent of US gun deaths), domestic violence, violence against police, and mass shootings.

As a breakthrough analysis by UC Berkeley’s Franklin Zimring and Gordon Hawkins in the 1990s found, it’s not even that the US has more crime than other developed countries. This chart, based on data from Jeffrey Swanson at Duke University, shows that the US is not an outlier when it comes to overall crime:

Instead, the US appears to have more lethal violence, driven in large part by the prevalence of guns.

“A series of specific comparisons of the death rates from property crime and assault in New York City and London show how enormous differences in death risk can be explained even while general patterns are similar,” Zimring and Hawkins wrote. “A preference for crimes of personal force and the willingness and ability to use guns in robbery make similar levels of property crime 54 times as deadly in New York City as in London.”

In many ways, this is intuitive: People of every country get into arguments and fights with friends, family, and peers. Every country has extremists and other hateful individuals. But in the US, it’s much more likely that someone who’s angry or hateful will be able to pull out a gun and kill someone, because there are so many guns around and few barriers to obtaining the weapons.

Researchers have found that stricter gun laws could help. A 2016 review of 130 studies in 10 countries, published in Epidemiologic Reviews, found that new legal restrictions on owning and purchasing guns tend to be followed by a drop in gun violence, a strong indicator that restricting access to guns can save lives. A review of the US evidence by RAND also linked some gun control measures, including background checks, to reduced injuries and deaths. A growing body of evidence from Johns Hopkins researchers also supports the efficacy of laws that require a license to buy and own guns.

That doesn’t mean bigots and extremists will never be able to carry out shootings in places with stricter gun laws. Even the strictest gun laws can’t prevent every shooting.

Guns are also not the only contributor to violence. Other factors include, for example, poverty, urbanization, alcohol consumption, and the strength of criminal justice systems.

But when researchers control for other confounding variables, they have found time and time again that America’s loose access to guns is a major reason the US is so much worse in terms of gun violence than its developed peers.

America, with its lax laws and abundance of firearms, makes it uniquely easy for people to commit horrific gun violence. Until the US confronts that issue, it will continue to see mass shooting after mass shooting.

For more on America’s gun problem, read Vox’s explainer.