You are probably aware, after a decade-plus of exposure to the idea of blogging, that bloggers live in their parents' basements. There are rarely exceptions to this in popular culture; unlike hackers, who extort and steal secrets and money from behind screens that project code onto their faces, bloggers are weaselly youngsters in tattered Primus t-shirts who call upstairs for more Doritos and Mountain Dew.

The data, however, refute that stereotype. And who better to present that exculpatory evidence than a blogger, who happens to be writing this from his mother's house but 1) not from the basement and 2) only because I am here visiting.

As is so often the case, it seems that we can blame the stereotype on the Washington Post. One of the first articulations of the blogger stereotype logged in the news index Nexis appeared in a December 2002 column about working from home, titled "When the Boss Is Omnipresent, There's No Place Like Home" and written by Catherine Getches.

"I dropped my to-do pad and gasped as I pictured something out of 'Night of the Living Dead,'" Getches wrote, "with hordes of Web publishers, bloggers and online junkies emerging from their basements, stumbling into the open air, shading their eyes from the sunlight." The context for this isn't important; what's important is where Getches placed those bloggers: basements.

It recurs: During Sarah Palin's 2008 interview with Greta van Susteren after her ticket lost the presidency, Palin wished the media would have reported some facts instead of "going on some blogger probably sitting there in their parents' basement, wearing their pajamas, blogging some kind of gossip or -- or a lie."

The pajamas comment we can't really evaluate. But the parent's basement thing? Almost always wrong. Out of the entire possible population of American bloggers, the chart at right indicates the percentage that might possibly live in their parents' basement, the result of a calculation that required answering three simple questions:

1. How many basements are there?
2. How many bloggers are there? and
3. How many people of bloggers' age live with their parents?

And here are the answers.

How many basements are there?

This, perhaps surprisingly, is the easiest one to answer.

Camille Salama of the real estate site Zillow provided me with data on the number of homes in the United States. To wit:

There are about 133 million housing units in the United States, not all of them occupied, according to the Census Bureau. About two-thirds of those are 1-unit buildings -- standalone houses. About 42 percent of those standalone houses have basements, either full (32 percent of the total) or partial (9.8 percent).

That is very literally the maximum number of basements that could be home to a blogger. The next question is how many bloggers those basements need to house.

How many bloggers are there?

To calculate this, you just need to figure out how many people blog, and then add them up.

Once you figure out what "blog" means.

"Blog" made its first appearance in the Washington Post fairly early, in June 2001. At that point, a blog was a tangible thing, a series of timestamped entries using blogging software. But then that became a sort of default on the Web. News sites and personal sites and corporate sites became or incorporated blogs to the extent that the word became more useful as a descriptor for someone who writes online than for a particular type of online content. So how many bloggers are there?

In the pre-social-media era, bloggers were counted by tool use. A 2009 estimate put the count at 452,000; by July 2012, a survey had the number at 31 million. Once you didn't need to log on to a blog tool to blog, those counts became difficult.

But last month, technologist Dave Winer -- credited by the Guardian as having invented the blog -- wrote a blog post about what a blog is, which is appropriately meta. If an article "was one voice, unedited, not determined by group-think -- then it was a blog, no matter what form it took," he wrote. "If it was the result of group-think, with lots of ass-covering and offense avoiding, then it's not."

It's not the case that you can identify a blogger by the tool he uses, as Winer told me over e-mail. "It's not the software that makes the blog," he wrote. "You could write press releases in WordPress, those would not be blog posts." So when your friend remembers a touching story from college in a long Facebook post, that's a blog. When Netscape founder and venture capitalist Marc Andreesen goes on a Twitter rant, that's blogging, too.

If a "blogger" is anyone who blogs, ever, professionally or not, then perhaps we should count the most recent count of monthly average users from Facebook (208 million in the U.S. and Canada) or Twitter (63 million in the U.S.). Or we could count Tumblr (17 million users in 2014, or people on Medium, or people on Snapchat, or people on Ello.)

We get a weird range, relative to the population of the United States (in the relevant year).

For our purposes, we're counting a subset of the Facebook number, a subjective percentage of the 208 million North Americans that post to the most popular social network in the world. About 140 million Americans use Facebook, according to Pew Research -- 58 percent of the population over 18. And I figure, based on a totally unscientific skim of my Facebook feed, that about three-quarters have at some point used the tool as a blog. That's 106 million bloggers in the United States.

And only 38 million basements.

Or, really, fewer. There's another factor that comes in to play. A lot of people in America live in California and Florida, the two most populous states. Most houses in those states, though, don't have basements. In the north, basements are more common, because the foundation needs to be beneath the frost line during the winter. In a 2010 survey of bloggers, Technorati found that California was the most common home to bloggers, followed by New York (lots of basements), Texas (few basements), and Florida (few basements). Where do all of those bloggers live?

As we're about to find out, not in their parents' basements.

How many bloggers live with their parents?

The Census Bureau put the number of households in the United States at about 115.6 million in 2013, 81.4 million of which were family households (meaning family members living together). In 2008, Pew Social Trends found that 49 million people were living in multi-generational households -- meaning that probably 20 million-or-so of them were living with a parent, including elderly ones.

The likelihood that anyone (blogger or not) lives with his or her parents varies by age. That 2008 assessment came at the tail end of the recession, a disruption that we can't trust to reflect living situations today. An assessment in 2013 put the number of 18 to 31 year-olds living with their parents at 21.6 million -- all of whom could fit into America's 29.1 million non-partial basements. Millennials under 25 were far more likely to live at home than those 25 to 31; only 16 percent of the latter group did so compared to 56 percent of the former. There's a caveat, however. Kids who live at college are counted as living in their parents' houses. And since Millennials spend more time in college, that explains part of the phenomenon. (Other factors: Lower rates of marriage and, again, the economy.)

Those young people are probably the sweet spot for the stereotype. Young people are more likely to use online tools, with 89 percent of those under 30 use social networking sites, according to Pew Research. Half of those over 65 do as well, and there are certainly older people who live with their older-still parents. That figure is almost certainly a much smaller number. The generation that is most into social media tools and into blogging is those who are younger.

So let's put it all together.

Putting it all together

Let's break this into four groups. There are those under 18, who I will ignore. Then there are those 18 to 24, those 25 to 31, and those 32 and older. (We're breaking out the younger users because of the live-at-home data.)

1. Members of the age group, 2014
18 to 24: 31.5 million
25 to 31: 30.2 million
Over 31: 180.9 million

On average 86 percent of all adults access the Internet -- but 95 percent of those under 33 do.

2. Those who are online
18 to 24: 29.9 million (95 percent of 31.5 million)
25 to 31: 28.7 million (95 percent of 30.2 million
Over 31: 155.6 million (86 percent of 180.9 million)

3. Those who use Facebook
18 to 24: 25.1 million (84 percent of 29.9 million)
25 to 31: 24.1 million (84 percent of 28.7 million
Over 31: 93.4 million (60 percent of 155.6 million)

Bloggers, we estimate, are 75 percent of those figures.

I applied the percentage living in each type of housing evenly, even though data suggests more tech use in cities (where there are fewer houses) and in more populous areas (like California and Florida, above).

4. Those who live in a home with a basement
18 to 24: 5.4 million (28.6 percent of 18.8 million)
25 to 31: 5.2 million (28.6 percent of 18.1 million
Over 31: 20 million (28.6 percent of 70 million)

Then, I figured out how many were likely to live at home, using a made-up estimate of 2 percent for those over 31.

5. Those who live with their parents
18 to 24: 2.7 million (51 percent of 5.4 million)
25 to 31: 820,000 (16 percent of 5.2 million
Over 31: 400,000 (2 percent of 20 million)

Giving us our graph.

There are, by our calculations, just under 4 million bloggers who possibly live in their parents' basements, out of 107 million total. Of course, many/most probably live in bedrooms like normal people, but this is the estimated maximum. Under 4 percent of all bloggers. The stereotype is a myth.

Now if you'll excuse me, I need some more Doritos.