When Dairrai Doliber walks into class at 7:40 am to teach high school social studies, there’s a good chance she’s only slept five hours. That’s because she was probably working as a cashier until 9:30 or 10 the night before.

The 32-year-old teacher in suburban Detroit works up to 20 hours a week at a clothing store, earning minimum wage to help supplement her $38,000 full-time teacher salary. She also takes night classes to get a master’s degree, which would hopefully boost her salary when she graduates in a few years.

“I can’t remember the last time I had a day off,” Doliber told Vox during one of her breaks. “I always had this understanding that I would never be rich as a teacher, but I never thought it would be this difficult to live on a teacher’s salary.”

Public school teachers have been known to work second jobs during the summer, but they are more likely than ever to also juggle multiple jobs during the school year. During the 2015-’16 school year, 17.9 percent of public school teachers surveyed worked another job, according to the latest data from the National Center for Education Statistics (NCES). (After-school coaching and other extracurricular activities are not counted as part-time jobs in the survey.) It’s the largest percentage reported in more than 10 years and is slightly higher than it was at the height of the Great Recession.

Public school teachers are now about five times more likely than the average full-time US worker to have a part-time job. Only about 3.3 percent of full-time workers in the United States had a part-time job in 2016, based on averages calculated with figures from the US Bureau of Labor Statistics.

A different data set, based on another national survey by the Bureau of Labor Statistics, also shows that teachers are likelier to work a side gig, though the gap between the two groups is smaller.

In recent weeks, dozens of teachers across the country have sent in their stories to Vox about how hard it is to make a living as a teacher in America. Many expressed their frustration about how they’ve had to take on one or two extra jobs just to make ends meet. That’s because they haven’t gotten a raise in years or the raises have not been enough to keep up with cost of living. As Vox’s Alvin Chang notes, public school teachers are earning less than they did 10 years ago after adjusting for inflation.

Before the first class bell rings, many teachers deliver newspapers, drive buses, or do custodial work. After class and on weekends, they might work as supermarket cashiers, Lyft drivers, or restaurant servers. It’s exhausting.

“I didn’t know it was going to be this hard to make a living,” said Victor González, a high school ESL teacher in Oklahoma who works two part-time jobs during the week — one as a custodian and another as a digital video operator. “We’re still figuring out how to make ends meet.”

The growing financial stress has become the central focus in the battles over teacher pay playing out across the country, from West Virginia to Oklahoma to Arizona. Teachers say going on strike is the only way lawmakers will listen. It worked in West Virginia.

States are spending less on education than before

One of the reasons teachers are making less money and juggling more jobs is because US public schools are experiencing a funding crisis. The crisis began during the Great Recession as tax revenue dried up and lawmakers cut state budgets. Then it got a lot worse in red states like Oklahoma and Arizona after lawmakers slashed income and business taxes.

The US economy has recovered, and wages for private sector workers are starting to rise. But teachers aren’t seeing their situation improve. Most states are still spending less on education than they were before the recession, according to an analysis from the Center on Budget and Policy Priorities. Lawmakers in West Virginia, Oklahoma, and Arizona have resisted pressure to raise taxes to pay teachers more or increase funding for public schools.

That’s why Oklahoma teachers have been sharing pictures like these in recent weeks:

Teachers say they have to work extra jobs to pay the bills

Teachers have historically ranked at the top of the list of workers most likely to have a second job, along with social workers and firefighters.

That’s likely a combination of several factors, says Dick Startz, an economics professor at the University of California Santa Barbara. Teachers have skills that make it easy to get jobs as after-school tutors, they have set schedules that allow them to pick up evening shifts, and, of course, they are notoriously underpaid.

“The low level of teacher pay is incredibly concerning,” said Startz. “When you have higher pay, there are two possible effects: You give people an incentive to work harder or you attract a different set of people into the workplace.”

Teachers who responded to Vox said they have to work second jobs to pay their bills.

Nancy Muñoz, a special education teacher in suburban Phoenix, said she started driving for Lyft a few years ago and has been doing online tutoring to pay her mortgage and student loans.

Her salary of about $50,000 doesn’t stretch as far as it used to. Muñoz and her husband, who works as a computer programmer, have had to refinance their home four times to help ease their financial burden. They couldn’t even help her daughter pay for college.

“I don’t think [society] values the work we do because they think anyone can teach,” said Muñoz.

Arizona teachers asked state lawmakers for a 20 percent raise. While it seems like a huge pay bump, salaries for teachers in the state haven’t kept up with the cost of living. Average salaries for teachers in Arizona, adjusted for inflation, have been cut by 12.9 percent since 2003.

Most of the 20 percent raise would make up for the increase in the cost of living. The state’s Republican governor, Doug Ducey, rejected the request and said teachers will have to stick with the 1 percent bump they passed last year.

Help our reporting on teacher salaries Are you a teacher who has seen your pay stagnate or go down over the years? Fill out this form.

Is it possible that the rise of the gig economy has made it likelier for people who otherwise wouldn’t work a second job to go out and have a side gig? The gig economy has certainly made it easier for US workers to moonlight, but teachers I spoke to who drive for Uber or Lyft said they would have to find another part-time gig if that wasn’t an option. All the teachers I spoke to, and all those who mentioned working second jobs in Vox’s survey, said they had to take a second job to pay their bills. None said they did it for extra spending money, though it’s possible that many teachers do so.

Economists at Harvard and Princeton conducted one of the largest studies on the subject, which showed a large increase in the share of US workers employed in the gig economy from 2005 to 2015. However, they said the sample did not allow them to determine if the trend made it more likely for workers to hold multiple jobs.

Teachers say they’re exhausted during the school day

There is little research on teachers who work multiple jobs, so it’s hard to measure the impact on their lives or their careers.

A 2011 study by researchers at Northwestern University and California State University found that working extra hours at an outside job was linked to higher levels of teacher burnout and a lower commitment to teaching.

The study surveyed a small sample of 461 high school teachers who also coached sports and debate teams in 46 states and the District of Columbia. It did not look specifically at teachers who work off campus.

But the impact on teacher morale mirrors the experience of teachers who talked to Vox. All four who spoke to Vox said they have thought about quitting at some point because of the financial stress. So did many teachers who wrote in to Vox.

“I love the kids, but it’s exhausting,” wrote Michele Dunaway, a high school teacher in Missouri. “There’s a reason that teachers leave the profession and a reason why young teachers aren’t going into this job, or that districts like mine can’t find qualified people. If you want great teachers, you have to pay them. Or they will go somewhere else and make more money. No one should have to work three jobs to make ends meet.”

Working multiple jobs also affects their teaching.

Annie Johnson, an ESL teacher in Pinellas County, Florida, says teaching private GED classes four hours every evening often leaves her feeling “mentally numb.”

“I don’t feel like I’m on the mark,” said Johnson, who has a master’s degree and 24 years of teaching experience, and earns $52,000 a year. “I have so many plates spinning. I always wonder if I am giving 110 percent like I should.”

Dairrai Doliber, the social studies teacher in Michigan, echoes her thoughts.

“I am constantly striving to create lessons that I know are engaging for my students, and to improve on those lessons, but there are definitely days when I come in and my energy level isn’t quite there,” Doliber told Vox. “I can’t help but think, if only I had a bit more time I could have made it a better lesson.”

Public school teachers in Oklahoma went on strike Monday, demanding state lawmakers raise their pay. They haven’t gotten a raise in 10 years, and Oklahoma ranks 49th in average teacher salaries.

In the teachers’ private Facebook group, Oklahoma Teacher Walkout, an algebra teacher in Yukon, posted this message.

“I coach 2 Sports, Uber, Lyft, Drive a School bus route, drive for ‘Party Bus OKC,’ and umpire little league ... all to help pay bills (and miss a lot of time at home with my 2 small girls to do it). I know I’m not the only one who has to do this. What are your ‘side-gigs’? Go.”

He got 1,300 responses.

Help our reporting on teacher salaries

Are you a teacher who has seen your pay stagnate or go down over the years? Fill out this form.