Dre Finley, 24, has a college degree and works at Arby's for $8.78 an hour. He has a 5-year-old daughter and another baby coming soon.

NEW YORK (CNNMoney)

Older. Educated. A parent.

This is the face of today's fast food workers -- 70% of whom are over the age of 20, nearly 40% have children and a third of them have spent some time in college, according to U.S. census data.

It wasn't always this way.

In 1979, teenagers held 26% of all low-wage jobs, while adults aged 25-64 made up less than half of such workers, according to the Center for Economic and Policy Research, which analyzed the low wage workforce over a 30-year span.

Today, only 12% of low paying jobs are held by teenagers, while adults make up 60% of them. Also, only 20% of such workers had attended some college in 1979. Today, it's 33%.

In essence, people working at a McDonald's (MCD, Fortune 500), Burger King (BKW) or Wendy's (WEN) are older and more educated, but earning some of the lowest wages in the economy.

Related: Workers willing to be arrested for $15 minimum wage

They look more and more like Dre Finley, who earns $8.78 an hour at Arby's in Tampa, Fla. He is 24, has a five-year-old daughter and another child on the way. Finley also holds an associates degree from a community college.

"Some customers think you're stupid because you're behind the counter, but I have an education," said Finley.

And Finley is not alone in not being able to convert his degree to a better-paying job. Job choices have become limited -- 44% of American jobs created in the past four years have been in low wage industries like fast food, according to the National Employment Labor Project, a liberal labor rights advocacy group.

"There's a classic mismatch. Fast-food jobs don't require high degrees," said Christopher Flynn, an economics professor at New York University.

A key argument behind the latest wave of strikes to raise wages to $15 an hour is that fast food workers these days are no longer just teenagers looking for pocket change. They are mothers and fathers struggling to raise children on wages that are too low, in most cases below poverty level.

Research also shows that fast food companies haven't shared their profits equally among their workers. While the lowest paid have not seen a raise in a long time, the industry's top management are not only being paid handsomely but have given themselves hefty raises.

Related: "My boss doesn't rule my destiny"

Public policy group Demos says CEO compensation in the industry just since 2000 quadrupled to $24 million, while average fast food worker's wage only increased 0.3%.

Fast food CEOs also make 1,000 times more than the average worker in the industry.

"The idea that you can work hard and play by the rules and get ahead is disappearing for a large number of American workers," said Catherine Ruetschlin, an analyst at Demos. "As for the American Dream, it's not as easy as people think to leverage into upward mobility from low wage jobs."

Tanika Smith, a 25-year-old with a college degree, says her $8.75 hourly wage has barely budged since she started seven years ago at a McDonald's in Chicago.

"I never imagined working at a fast food place with a B.A. I imagined I'd be working downtown at a law firm making major bucks," says Smith, who hopes to earn a master's degree and aspires to be a judge.

Tanika Smith, a McDonald's worker, has a B.A.

"The people I work with now are not comfortable doing what they are doing. It's not what they want - but that's where the jobs are," Smith says.