NEW YORK (MainStreet) - Welcome to the Age of the Roommate.

In yet another sign that our much-touted economic recovery isn't all it's cracked up to be, real estate website Zillow is out with a new study tracking how people rely on roommates to help make ends meet. They call it "doubling up," moving in with another adult other than a romantic partner to save money, and it's a lot more common than it used to be. From the study:

As rents rise and income growth remains flat in many areas, renters are increasingly forced to devote an ever-larger share of their monthly income towards rent. In the second quarter, a typical American renting household spends 29% of their income on rent, compared to 25% in 1990 and 24% in 2000.

Nationally, 32% of working-age adults - aged 23 to 65 - live in doubled-up households, up from 25% in 2000 and 26% in 1990.

Approximately one-third of working adults now live with a roommate, an increase of about 25% since 2000. Even worse, Zillow shows this increase stretching back to 2000 with no signs of slowing down.

In the cities things get particularly bad. Almost half of the working adults in places like Los Angeles and Miami live "doubled up," while New York gets away with only 42%. Although people tend to make more money in metro areas, those incomes simply haven't kept pace with the local housing markets. Rent demands an ever higher share of earnings, pushing more and more people into a second bedroom whether they like it or not.

In fact stagnant incomes drive this trend nationwide. Although some, like Thomas Friedman celebrate the idea of people having to rent out their homes or cars as a way to make ends meet, the reality is that Americans are struggling. We haven't pawned our privacy, because we want to. We did it to survive. Gen X-ers and Baby Boomers haven't seen a functional raise in years, while Millennials struggle to get any kind of career started. Paychecks haven't even kept pace with inflation, and thanks to that the average American now has about the same spending power as he did back in 1979. While we were losing four decades, costs of living continued to go up. Sooner or later something had to give.

And it did.

"There's a strong correlation between the share of adults who live in a doubled up household and the share of income that a household has to spend on rent," said Skylar Olsen, a senior economist with Zillow and author of the study. This is particularly true in the cities, she added: "More expensive metros mean more doubling up."

Now, some people like living with roommates and prefer to do so. (There's much to be said about having a buddy around with whom to share a beer and watch inexplicable Japanese game shows.) However the data is pretty clear that doubling up has much more to do with economics than friendship. The average doubled up household makes 76 cents on the dollar compared to all adults, and even among American cities the ones with more expensive rent consistently have more adults living together.

To drive the point home Zillow also tracked the average share of household income spent on rent since 1990. Unsurprisingly, its growth correlates almost exactly.

From Millennials moving back in with mom and dad to middle aged Manhattanites who keep putting off dreams of their own home, more and more people are having to share space just to get by. For them, privacy is now just another luxury deferred by an economy that we're told has recovered... for somebody out there.

In a Catch-22, one solution appears to be buying your own home instead of renting. Mortgages are cheaper than renting, sometimes by vast amounts. According to Zillow's data, a mortgage can cost half as much as a share of income compared to monthly rent (30% compared to 15% nationwide). The problem is, with people having to spend more and more just to keep a roof over their heads, not to mention the student loan payments that have kneecapped so many Millennials, saving for that down payment is often little more than a pipe dream.

"That's one of the things that we're worried about, is the ability of would-be first time home buyers to get into the game," Olsen said. "For housing demand to come back from these doubled up households we're going to need to see more income improvement, and the tough rub that I think we're seeing from these millennials is the difficulty in savings. If you're paying more out of your income in rent, the share that leads to doubling, and you're paying more out of your income with student debt... that leaves very little room to save for a down payment."

"Will they be able to buy homes and participate in the housing market due to these barriers to savings?" she asked.

It will probably be a while.

--Written for MainStreet by Eric Reed, a freelance journalist who writes frequently on the subjects of career and travel. You can read more of his work at his website www.wanderinglawyer.com.