Gun suicide is one of the leading causes of death in the United States, yet gun ownership continues to rise.

In the decade since the Sandy Hook massacre, 150 million firearms have been purchased by Americans. A survey from Harvard and Northeastern University found that the number of people who own guns rose by 20 million since 2015, from 55 million to 75 million. According to Gallup, one-third of Americans say they own one or more firearms.

Though it's not just guns stored in the home, as 16 million Americans say they carried a firearm in public at least once a month. Around 6 million do so daily. Both are near double the amount reported in 2015.

Experts cite the Covid-19 pandemic and growing political polarization as motivations behind the surge in firearm sales. In fact, in 2020 and 2021, 5 million people became gun owners.

Among gun owners, 88 percent cite their reason for purchasing firearms as "crime protection." A survey of California residents found concerns about "lawlessness," "people being released from prison," “government going too far,” and “government collapse.”

Jennifer Carlson, a sociologist who studies US firearms culture, told The Guardian that the prevalence of guns in society leads to people believing they are a viable option for defense.

“When social problems happen, guns are one of the tools at the disposal of Americans, and for many Americans, they are a familiar tool," she said. "If there’s a run on toilet paper, what’s going to be next? It’s just the prudent thing to get a gun.”

The January 6 insurrection on the US capital also lead to a surge in gun ownership. Though it isn't conservatives who were motivated to buy, as women account for half of new firearms purchases since 2019. Between 2019 and 2021, 5 percent of Black Americans also bought a gun for the first time.

Because of the lackluster data and restrictions on firearms, it is difficult to estimate how many people own guns in the United States. Experts say it could be anywhere from 345 million to 420 million.

Matthew Miller, a Northeastern University professor who specializes in firearm research, believes that the unregulated gun industry often leads to transactions taking place under the proverbial table.

"What matters is how these guns are distributed across people and households," he said.

Widespread firearm ownership routinely leads to gun suicide, homicide, or accidental injury. Data from the Centers for Disease Control and Prevention estimates nearly 21,000 firearm homicides and more than 24,000 firearm suicides in the United States in 2021.

Experts say the best way to curtail gun violence is through background checks, and laws mandating gun registration and data collection.