It's not just victims of homicide whose lives would be saved by tougher gun laws.

Content note: This post concerns suicide and may be triggering to some readers.

We keep reading and reading and reading about the number of people guns are killing in America.

Sunday night’s attack in Las Vegas, in which one man broke two windows 32-floors high and rained bullets upon a crowd of 22,000 using a room full of guns that had been rigged to fire like automatic weapons, ignited the conversation. Again.

Fifty-nine people died – the biggest mass shooting in modern American history – for us to read about the number of people guns are killing in America and what might be done to stop it.

In 2015, that number was 36,252. In 2014, it was 33,594. In 2013, it was 33,636.

What we don’t read about is the number of these deaths that are suicides.

Of the 36,252 people who died by firearms in 2015 in the US, 12,979 of these deaths were homicides, according to the National Center for Injury Prevention and Control. Almost double this number – 22,018 of these deaths – were suicides using a firearm.

In 2014, the number of suicides with a gun was 21,386 compared to 11,008 homicides. In 2013, it was 21,175, compared to 11,208.

The numbers show one clear truth: the majority of gun deaths in America are suicides.

And that’s one more argument – one we rarely ever hear about – for tougher laws around gun control.

First, we’ll look to Australia.

The number of suicides by firearms in Australia declined drastically in the years following the 1996 gun buyback that came after the Port Arthur Massacre.

According to research conducted by the Australian National University and the Wilfrid Laurier University in Ontario, Canada, firearm suicides in Australia dropped from 2.2 per 100,000 people in 1995 to 0.8 per 100,000 in 2006. A drop of 65 per cent.

But what about suicides by other methods? What about suicide trends in general?

Numbers show us that in that same time period – between 1996 and 2006 – the rate of suicide fell by 27 per cent in general – something that could be put to other factors: Way of life, improving economy, better health outcomes, the list goes on.

There was also an up-kick in the number of non-firearm suicides between 1997 and 2000 – did that mean people had given up their guns, just to take their lives using alternative methods?

These researchers, lead by Andrew Leigh in Australia and Christine Neill in Canada, wanted an answer: did the gun buyback really make a difference?

“Our results show that the jump [in the number of non-firearm suicides in the period 1997-2000] occurred primarily in the states where the fewest guns were handed in, and where the gun buyback would have been expected to have the least effect,” the report concludes.

In Tasmania, where 34,584 guns were handed in, both the firearm suicide rate and the non-firearm suicide rate dropped after 1996.

In the Australian Capital Territory, where only 5,246 guns were handed in, the non-firearm suicide rate increased, and the firearm-suicide rate stayed somewhat the same, in the years directly after the buyback.

“Our estimates suggest that Australia’s buyback would have averted more than 200 firearm deaths per year – mostly suicides – in a population roughly the size of Australia’s,” the authors conclude.

What do we learn from this? That guns are a risk factor for suicide.

Harvard University agrees.

“Every study that has examined the issue to date has found that within the U.S., access to firearms is associated with increased suicide risk,” the Harvard University’s School of Public Health webpage states.

It references 12 “case control” studies that have found those who die by suicide are more likely to live in homes with guns.

One study, published in the Journal of the American Academy of Child and Adolescent Psychiatry looked at 47 teens who’d died by suicide; 47 who were in hospital after a suicide attempt; and 47 psychiatric patients who had never attempted suicide.

The results? “Those who died by suicide were twice as likely to have a gun at home than either of the other two groups,” the report concludes.

Then, there is America on a larger scale, looking at the difference in suicide rates between those states with the lowest firearm prevalence (total population 40 million), and those states with the highest firearm prevalence (population 39 million).

In places of high gun ownership, where at least 47 per cent of households have a gun, a 2007 study published in the Journal of Trauma found there was a total of 14,809 suicide deaths between the years 2000 and 2002. 9,747 of these deaths were from a firearm.

In those states with fewer guns (14 per cent of houses), the number of firearm suicides was much lower – 2,606. But the number of suicides in general was significantly smaller, also.

There were only 8,052 suicides between 2000 and 2002 in lower gun states, compared to 14,809 in higher gun states.

It’s the risk factor effect.

Maybe it's availability. That a house with a gun in it means a 'way out' is right there staring you in the face. We saw this in the 1960s in England, when they changed the oven technology to use natural gas as opposed to coal gas.

In the first half of the 20th century, many people were taking their lives by inhaling oven fumes. Suicide didn't stop once the ovens changed, but it certainly slowed. When the means for suicide wasn't right there in the home, only some people sought out a different method. Others didn't try again.

It's definitely a matter of effectiveness - these studies don't look to suicide attempts. Perhaps the numbers around trying and failing to suicide are larger in states with fewer guns. There is more room to 'fail' and more time to reconsider. A bullet is fast and accurate and there is no turning back once the trigger is pulled.

Reasons aside, would policy making change the numbers?

Yes, if we look to Australia.

Yes, if we look to history.

Yes, if we look to the states in America where there are fewer guns in homes.

On Sunday, 59 people died because of one madman with a gun hanging out of a 32nd floor window.

This year - if the previous years are anything to go by - more than 20,000 people in America will take their own lives using a firearm. At least some of these deaths will be preventable.

What more needs to happen before we stop reading about gun control, and something changes, instead?

How many more lives need to be lost in order to prove: whether it's suicide, or homicide, tougher gun control will save lives.

If you or a loved one is struggling, help is available at Lifeline on 13 11 14.