Housing, as we've mentioned a couple of times, has been growing more expensive, particularly for the poor. This isn't simply a phenomenon of the last few years, as former homeowners have crowded into the rental market and as new construction stalled thanks to the recession.

Housing costs, adjusted for inflation, have been rising for the last two decades (at least). This chart, from a new Pew report using the Bureau of Labor Statistics’ Consumer Expenditure Survey, shows that while this expense has been inching up for everyone, the poorest third of Americans now spend about 50 percent more on all their housing costs — including utilities and repairs — than they did back in 1996:

Image: Pew

Consider that alongside the fact that incomes have stagnated over this time, and the share of household income going to housing has crept uncomfortably high, leaving many poor renters paying as much as half or more of their income on housing.

What's worse is that this isn't the only major expense that's gotten larger over this same time. Transportation costs have risen, too. According to Pew's analysis -- which focuses on the working-age population of Consumer Expenditure Survey, respondents aged 20-60 -- the poorest third of families spent more on gas in 2014 than on all of their transportation costs combined in 1996:

Image: Pew

Pew calculates that median household expenditures, including everything from health care to housing to food and entertainment, grew by 25 percent from 1996 to 2014. Given that incomes haven't kept pace, that means that most families have less and less money left over after all their spending. And, again, for the poorest third, that leaves them in a particularly dire position.

This last chart from Pew shows how much income households were left holding — their financial slack — in 1996 and in 2014 after all these expenses. This is the money that helps build wealth, that pays for college later on or retirement down the road. Even for the wealthiest third of families, that sum has dropped considerably since the mid '90s. But for the poorest, it's put them in the red. Back in 1996, a typical family in the bottom third had about $1,400 of income left over after expenses. Now they're in debt by about $2,300.

We tend to focus more on the money families have coming in, and the stingy rate at which those incomes are rising. But growing expenses for many basic needs make that picture even worse:

Image: Pew