A story about striking janitors in Houston encapsulates many of the themes that Marketplace's Wealth and Poverty desk covered throughout 2012. Pictured: One of the striking janitors, Lorenza Delgado. Krissy Clark/Marketplace - 

This year in Wealth and Poverty: Janitors, the middle class and the fiscal cliff.

You’ve heard us talk all year about issues pertaining to the wealth gap -- who’s getting richer, who’s getting poorer and what’s next for the middle class. And it’s been a big year for those questions. The issue of economic inequality took center stage during the election and is getting a starring role in the fiscal cliff discussions happening now. Marketplace senior reporter Krissy Clark takes us on a tour of some of the biggest -- and smallest -- Wealth and Poverty themes of 2012.

Which wealth and poverty story stood out most in 2012?

Clark says that one of the most important stories of 2012 didn’t make a lot of headlines.  Over the summer, she covered a group of striking janitors in Houston.  The Houston skyline is crowded with skyscrapers that house executives of the some of the richest companies in the world like Exxon Mobil and JPMorgan Chase. The people who clean these buildings, however, are paid very little. They went on strike to try and raise their wages over the next several years.

“These offices are a microcosm of the income inequality that’s been growing across America during the past few decades,” says Clark. Companies and executives are making record profits, but wages at the other end have stagnated, she says.

Are we getting to a point where there will only be two classes in America?

Clark says that until fairly recently, a lot of Americans worked in manufacturing. These jobs were a pathway to the middle class for a lot of people, especially in the Midwest. Blue-collar jobs used to pay well enough so that people didn’t need a college degree to live comfortably. But Clark says we’re shifting away from that model of economic mobility.

“Now as the global economy is changing, a lot of those sorts of jobs are gone. What’s left in a lot of places are either professional jobs that require a lot of education and make a good amount of money or service jobs” said Clark.

These service jobs Clark mentions are mostly low-wage like the janitors in Houston. And going forward, Americans will face some tough questions about how to transform those low-wage jobs into middle-class jobs.

Other notable Wealth and Poverty Stories from this year:

-New Orleans' other 'million dollar neighborhood'

-The path to Michigan’s right to work law

-Falling into poverty: A family’s story

-Warehouse ‘permatemps’ push Walmart accountability

Follow Krissy Clark at @@kristianiaclark