Wooden storm windows on your house say you are upper class.

Driving a Mercedes-Benz shouts "middle class" as well as "vulgar."

And covering your couch with clear plastic – the horror! – announces with a screech that you're a working-class "prole" – proletarian.

That was the class system codified by Paul Fussell, the cranky, brilliant University of Pennsylvania literary historian and author of the 1983 book, Class: A Guide Through the American Status System.

These days, as the country debates inequality and contemplates how tax reform will affect the rich, the poor, and the middle class, figuring out exactly what class means gets tricky, and a bit more complex than Fussell delineated.

If you ask people whether they're poor, middle, or upper class, as many as 90 percent place themselves within the middle class, economists have long known. If, however, you add a fourth possibility – working class – around 45 percent will claim it, while another 45 percent will stick to identifying as middle class. No one will acknowledge being poor, and few if any will admit to being rich, said Michael Zweig, emeritus economics professor at the State University of New York, Stony Brook.

To determine what middle class means beyond what folks on the street say, the Pew Research Center in Washington calculated that a person is middle class if he or she makes from two-thirds to two times the median household income, which in 2016 was around $59,000.

That means you're middle class if you make between roughly $40,000 and $120,000 a year, a huge span.

Another way to figure who is middle class relies on a complex formula that combines race, education, and age.

Yet another uses a four-year college degree as the dividing line between working class and middle class. Around one-third of Americans have bachelor's degrees, census figures show.

These days, analysts like Zweig rely on a newer method of sorting out the knotty permutations of class. They eschew consideration of income, lifestyle, and education, and use what's called the power definition. That is, how much power do you have to control the pace and content of your work?

If you're a cashier or a factory worker, you don't have a lot of say over your hours and what you do. This makes you working class.

But if you're a union electrician or a big-city sanitation worker who has access to overtime and is making more than $100,000, you still may have little power on the job.

"This doesn't make them middle-class people," Zweig concluded. "They're working class with a decent standard of living."

By this definition, the working class is 63 percent of the U.S. workforce, Zweig said. Thirty-five percent is middle class – managers, small business owners, and professionals – all of whom have some authority over their own time or the time of others.

The remaining 2 percent are the so-called capitalists, who direct businesses, and rule Wall Street and other money kingdoms, he added.

The poor, Zweig said, are working-class people who suffer from unemployment, a lack of decent wages, and a dearth of health care.

These people have lately been assigned a new term — "the precariat," noted John Russo, working-class studies expert at Georgetown University. A lot of these are former middle-class victims of the recession, living precarious lives and unable to secure well-paying jobs.

Some will insist that class is conferred by family and won't ever really change. Allison Hurst, born working class and now a sociologist at Oregon State University, identifies as working class, even though her occupation and salary may make her seem upper middle class. "But that just doesn't align with my identity," she said.

Class, then, is more than economics. It extends into culture, religion, and other aspects of life – social capital, experts say.

"Class is also about how one lives one's life and what their expectations of the world are," Hurst said.

Compare a college-educated social worker who makes $50,000 a year and occasionally shops at Whole Foods, enjoys foreign films, and encourages her son to do a gap year in Costa Rica with a high-school-educated plumber who takes home $120,000 and likes eating wings from a local joint.

The Pew numbers say they're both middle-class by dint of their income. But in terms of the class intangibles of social capital, they likely do not share world views, and probably backed different presidential candidates.

"In the end, it's not their income that matters but their sense of space in the world," said Jane Van Galen, a sociologist of education at the University of Washington.

None of this is simple to figure out.

"My wife and I consider ourselves middle class," said Dan Mullen, 63, a safety worker for a crane company who doesn't have a four-year college degree. Together, he and his wife make around $100,000 (he prefers not to be specific). They own a house in the Northeast and don't have children.

What counts for Mullen is not a class label, but a question: "Are we better off than our parents?"

The answer is yes, and that means a lot, Mullen said.

"It's the American Dream," he said. "I made it this far, living in a nice neighborhood.

"We've done as well as we can."