There's a gun for every American. But less than a third own guns.

Gun ownership trending downwards

George Frey/Getty Images

(CNN) - The debate over guns in America has been renewed following the mass shooting in Florida on Wednesday. The discussion has followed a familiar script, with Democrats wanting to enact gun control and Republicans tending to focus on mental health issues.

As the discussion rages on, keep in mind the following five facts about gun ownership in this country.

1. We don't know how many people own guns

There is no countrywide database where people register whether they own guns (the law doesn't allow it). We have to rely on surveys instead. High quality telephone polls from Gallup and the Pew Research Center in 2017 found that 42% of people in the US live in households with guns. According to the General Social Survey, which has a much higher response rate than telephone polls and interviews people in person, a relatively lower 32% of Americans said in 2016 that they lived in household with guns. The gap between telephone and GSS surveys has existed in some form for 20 years, so it isn't just a one-off difference.

It's not clear which datasets are more correct. The GSS, with its high response rate, is generally thought of as the gold standard survey in understanding social trends in America. It is conceivable, though, that people may not want to admit to owning guns to people who are standing in front of them.

2. Gun ownership was trending downward, but now there is no trend

Households with guns are considerably down from previous decades. In surveys conducted in the first half of the 1990s, Gallup discovered that on average 48% of Americans lived in households with guns. The GSS showed a similar 45% during that stretch.

Since that time, Gallup has found an average of 41% of households with at least one gun compared with 35% of the GSS. Both of those are within a few percentage points of the average for this decade (41% for Gallup and 33% for the GSS). In other words, there was a sharp trend downward in gun ownership during the 1990s, which has since stopped.

3. Many people live in households with guns, but don't personally own them

So far we've looked mostly at households with guns in them. That's because pollsters will most often ask Americans whether or not they live in households with guns. That's clearly different than a person owning a gun him or herself, however. According to the 2017 Pew study, 30% of Americans own guns themselves (12 points lower than the 42% who live in households with guns). For Gallup, it was 29% (13 points lower than the 42% who live in households with guns). The GSS pegs it even lower -- only 21% of Americans said they personally own guns (11 points lower than the 32% who live in households with guns).

Both the GSS and Pew surveys find that it's women who are more likely to be the people who don't personally own guns but live in households with weapons. In fact, the GSS found that only a little more than a third of women in households with guns own one. Pew put it at a little more than half. Among men, both surveys determined that around 90% who live in households with guns own one.

4. Handguns are most common, but most gun owners have multiple types

Both Pew in 2017 and the GSS in 2016 asked gun owners whether they owned a handgun (pistol in the case of the GSS), rifle or shotgun. The GSS and Pew polls each found that a little over 70% of gun owners had handguns, while a lower percentage owned rifles or shotguns. Even for a shotgun though, which both surveys found to be the least common to be owned, a majority of gun owners in both the GSS (63%) and the Pew polls (54%) said they had one.

That gets to another key point: Gun owners like to own many guns. According to Pew, about two-thirds of gun owners have multiple guns. That's how you end up in a country where there's about a gun per person, even though only a third or less of people actually own guns themselves.

5. Gun ownership follows traditional political trends ... to a point

Republicans are more likely to own guns than Democrats. Whites are more likely to own guns than blacks. Men are more likely to own guns than women. People in urban areas are more likely to own guns than those in rural areas.

But while some of the gaps on who owns a gun generally match the partisan gap (as measured by 2016 presidential vote patterns), other gaps are smaller than you might expect given the great political divide on whether the country needs tighter gun control.

In the 2017 Pew data, for example, there was a 25 percentage point gap between the Democrats (16%) who owned guns and the Republicans (41%) who did. That's far smaller than the 80 point difference between how many Democrats (8%) and Republicans (88%) voted for Trump in the 2016 exit poll.

Additionally, the racial gap on gun ownership is smaller than you might expect. According to Pew, 24% of blacks own guns and 36% of whites do. In the 2016 presidential election, Trump won 57% of white voters compared with just 8% of blacks.

Copyright 2018 by CNN NewSource. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.