Some jobs offering low starting salaries can lead to the tripling of income in 20 years, according to a new Launchpad Jobs report from the American Student Assistance and Burning Glass Institute.

The report tracked jobs where workers were able to triple their salaries in the span of 20 years. This includes workers who started as restaurant hosts, coffee shop employees, motion picture projectionists, amusement attendants, door-to-door sales workers, news and street vendors, pharmacy aides and telemarketers.

All of these jobs offer low starting wages, at roughly $20,000 to $22,000 a year. But within two decades, those workers who had the jobs ended up making between $60,000 and $80,000.

“The common trend you notice in jobs that can produce double or even triple the starting income over the working lifetime of the employee is they normally involve industries where a new hire ‘working their way up the ladder’ is common,” Alex Beene, a financial literacy instructor at the University of Tennessee at Martin, told Newsweek.

“Very few people in the restaurant business, for example, start at the top and normally have to endure years of jobs at below-average wages before they start to see salary growth.”

Restaurant hosts started with a salary of $20,500, but 20 years later, they made a median income of $80,600. Similarly, for amusement park attendants and pharmacy aides, starting salaries were roughly $20,000, but 20 years later, they were making about $66,000.

“Whereas the low starting wages drives many away, those who stay put and see their skill set grow more efficient are more than likely going to see a dramatic upswing in their earning power,” Beene said.

The report also found a notable number of workers without college degrees ended up outearning the median college graduate. Roughly 2 million non-degreed workers earn more than $100,000 per year.

“You don’t need a degree to succeed, but you do need a map,” Matt Sigelman, president of the Burning Glass Institute, said in a statement. “We often hear that it’s grit that distinguishes those who achieve career success from those who wind up stuck. But luck-of-the-draw choices about which job to take can have a huge impact on a young worker’s chances of getting ahead.”

While some may be optimistic about the potential of tripling their salary, HR consultant Bryan Driscoll said many people who start out in these roles are forced to “claw their way” to a decent pay over decades.

“It’s not a victory lap to point out that with 20 years of hard work, someone might finally be able to afford a mortgage,” Driscoll told Newsweek. “These jobs top the list because, historically, they’ve been essential—though I definitely see some of them going away before long. However, our wage structures are so broken that workers have to rely on sheer time in the field to move the needle.”

Kevin Thompson, a finance expert and the founder and CEO of 9i Capital Group, said it makes sense that the longer one stays in an industry, the more they earn.

“The key takeaway is that value and experience usually win out, regardless of where someone starts,” Thompson told Newsweek. “That said, workers should be mindful of industries that are notorious laggards in wage growth. These industries often have lower barriers to entry, resulting in an oversupply of workers and consistently lower salaries, no matter how skilled you become.”

Driscoll said the question remains why these jobs didn’t start with higher wages.

“What’s shocking isn’t that someone can triple their salary, but that this is framed as exceptional when it’s really a reflection of how deeply undervalued workers are across industries,” Driscoll said. “What workers need to know is that salary growth shouldn’t be a pipe dream dependent on 20 years of loyalty.”