The American Dream has long promised that hard work leads to stability. But for teachers who dedicate themselves to preparing the next generation, long hours in the classroom aren’t translating into financial security.

Over half of K–12 teachers report that they are just “getting by” financially—with one in five reporting they find it difficult to live on their present income, according to a new study by Gallup and the Walton Family Foundation. That financial strain has forced many educators to do what’s increasingly common across the workforce: pick up a side gig.

About 62% of educators are taking on additional work connected to education, like coaching or tutoring, but one in three work second jobs that have nothing to do with teaching, like driving for Uber, working in food service, or running a small business in the evenings or on weekends.

The financial pressure is hiding in plain sight. Public school K–12 teachers earn average salaries of $72,030, according to the National Education Association—more than the median annual wage of all workers of $49,000. But when adjusted for inflation, teachers make on average 5% less than 10 years ago, and 9% less than the peak in 2009–10. Many are also carrying significant debt: About 45% of educators have taken out a student loan to fund their education, with an average balance of $55,800.