Mothers working in the restaurant industry spend an outsize portion of their paychecks on child care, a new study finds, and in may cases, that money is going toward spotty care that does little to reduce the stress of working a low-paying job on an often unreliable schedule.

According to the study from the Restaurant Opportunities Center United, a restaurant worker advocacy group, mothers working as cooks, servers and in other restaurant jobs  spend on average 35 percent of their weekly income on childcare . That spending far  outstrips the 10 percent share of income the government recommends parents spend on child care, and the 25 percent share of each paycheck experts recommend you spend on your home .

About 2 million mothers work in the restaurant industry, according to the ROC report, and the findings are particularly troubling as the sector creates jobs at a faster clip than the overall economy — a trend that’s held for the past 14 years.

“This is a sign of the future,” Helen Blank, who is the director of child care and learning at the National Women’s Law Center and wasn’t directly involved in the research, told The Huffington Post. “More and more jobs that are being created are low-wage jobs with these unpredictable schedules.”

Compounding costs for restaurant workers are their oft-changing, sometimes inflexible work hours, which can force them to choose between spending as much as half of their paychecks on child care or using lower-cost, less reliable providers, Blank said. Only  10 percent of child care providers in the U.S. provide high-quality care, according to a  2007 National Institute of Child Health Development survey cited by The New Republic.

Restaurant workers often find their child care providers can be unreliable, causing working mothers to show up late, miss shifts and jeopardize promotion opportunities and their jobs,  the study found . When women can’t make it to work because a child care arrangement falls through, they can lose out in the short-term by not getting paid for hours they can’t work and in the long-term through disciplinary actions from their bosses.

“Often if you’re low-wage, even if that child care is a large proportion of your income, it still probably isn’t very high quality childcare,” said Ariane Hegewisch, the study director of the Institute for Women’s Policy Research. “Reliable child care is a really important factor in helping women stay on the job.”

Moreover, paying too much money to ensure their kids are taken care of may hurt working mothers’ earning potential.  Research shows that when women don’t have to worry about paying for reliable child care, they’re more likely to be employed and their wages are higher.